Vent arrangement for a respiratory device

ABSTRACT

A vent arrangement for a respiratory pressure therapy device may include one or a plurality of vents configured with a variable aperture for communicating a flow of breathable gas. The vent arrangement may be configured with a cross section profile exposed to the flow of breathable gas communicating through the vent that does not change as the aperture size changes. A vent arrangement may include a plurality of the vents and the aperture size of each vent may be controlled independently or together, and may be controlled according to one or more input signals from one or more sensors. Examples of suitable input signals include flow, pressure, noise, accelerometer outputs, orientation of a patient or presence of any obstructions. A patient interface or an air circuit may include the vent arrangement, or the vent arrangement may be configured to connect with a patient interface or an air circuit.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.14/776,352 filed Sep. 14, 2015 which is a national phase entry under 35U.S.C. § 371 of International Application No. PCT/AU2014/000263 filedMach 14, 2014, published in English, which claims priority fromAustralian Provisional Patent Application 2013903088 filed on Aug. 16,2013 and Australian Provisional Patent Application 2013900885, filed onMar. 14, 2013, all of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION (1) Field of the Invention

The present technology relates to one or more of the detection,diagnosis, treatment, prevention and amelioration of respiratory-relateddisorders. In particular, the present technology relates to medicaldevices or apparatus, and their use.

(2) Description of the Related Art

Human Respiratory System and its Disorders

The respiratory system of the body facilitates gas exchange. The noseand mouth form the entrance to the airways of a patient.

The airways include a series of branching tubes, which become narrower,shorter and more numerous as they penetrate deeper into the lung. Theprime function of the lung is gas exchange, allowing oxygen to move fromthe air into the venous blood and carbon dioxide to move out. Thetrachea divides into right and left main bronchi, which further divideeventually into terminal bronchioles. The bronchi make up the conductingairways, and do not take part in gas exchange. Further divisions of theairways lead to the respiratory bronchioles, and eventually to thealveoli. The alveolated region of the lung is where the gas exchangetakes place, and is referred to as the respiratory zone. See“Respiratory Physiology”, by John B. West, Lippincott Williams &Wilkins, 9th edition published 2011.

A range of respiratory disorders exist. Some examples of respiratorydisorders include: Obstructive Sleep Apnea (OSA), Cheyne StokesRespiration (CSR), Obesity Hyperventilation Syndrome (OHS), ChronicObstructive Pulmonary Disease (COPD), Neuromuscular Disease (NMD) orchest wall disorders.

Otherwise healthy individuals may take advantage of systems and devicesto prevent respiratory disorders from arising.

Therapy

Nasal Continuous Positive Airway Pressure (CPAP) therapy has been usedto treat Obstructive Sleep Apnea (OSA). The hypothesis is thatcontinuous positive airway pressure acts as a pneumatic splint and mayprevent upper airway occlusion by pushing the soft palate and tongueforward and away from the posterior oropharyngeal wall.

Non-invasive ventilation (NIV) provides ventilator support to a patientthrough the upper airways to assist the patient in taking a full breathand/or maintain adequate oxygen levels in the body by doing some or allof the work of breathing. The ventilator support is provided via apatient interface. NIV has been used to treat CSR, OHS, COPD, MD andChest Wall disorders.

Invasive ventilation (IV) provides ventilatory support to patients thatare no longer able to effectively breathe themselves and is providedusing a tracheostomy tube.

Ventilators may control the timing and pressure of breaths pumped intothe patient and monitor the breaths taken by the patient. The methods ofcontrol and monitoring patients typically include volume-cycled andpressure-cycled methods. The volume-cycled methods may include amongothers, Pressure-Regulated Volume Control (PRVC), Volume Ventilation(VV), and Volume Controlled Continuous Mandatory Ventilation (VC-CMV)techniques. The pressure-cycled methods may involve, among others,Assist Control (AC), Synchronized Intermittent Mandatory Ventilation(SIMV), Controlled Mechanical Ventilation (CMV), Pressure SupportVentilation (PSV), Continuous Positive Airway Pressure (CPAP), orPositive End Expiratory Pressure (PEEP) techniques.

Systems

A treatment system may comprise a Respiratory Pressure Therapy Device(RPT device), an air circuit, a humidifier, a patient interface, anddata management.

Patient Interface

A patient interface may be used to interface respiratory equipment toits user, for example by providing a flow of breathable gas. The flow ofbreathable gas may be provided via a mask to the nose and/or mouth, atube to the mouth or a tracheostomy tube to the trachea of the user.Depending upon the therapy to be applied, the patient interface may forma seal, e.g. with a face region of the patient, to facilitate thedelivery of gas at a pressure at sufficient variance with ambientpressure to effect therapy, e.g. a positive pressure of about 10 cmH2O.For other forms of therapy, such as the delivery of oxygen, the patientinterface may not include a seal sufficient to facilitate delivery tothe airways of a supply of gas at a positive pressure of about 10 cmH2O.

The design of a patient interface presents a number of challenges. Theface has a complex three-dimensional shape. The size and shape of nosesvaries considerably between individuals. Since the head includes bone,cartilage and soft tissue, different regions of the face responddifferently to mechanical forces. The jaw or mandible may move relativeto other bones of the skull. The whole head may move during the courseof a period of respiratory therapy.

As a consequence of these challenges, some masks suffer from being oneor more of obtrusive, aesthetically undesirable, costly, poorly fitting,difficult to use and uncomfortable especially when worn for long periodsof time or when a patient is unfamiliar with a system. For example,masks designed solely for aviators, mask designed as part of personalprotection equipment (e.g. filter masks), SCUBA masks or for theadministration of anaesthetics may be tolerable for their originalapplication, but nevertheless be undesirably uncomfortable to be wornfor extended periods of time, e.g. several hours. This is even more soif the mask is to be worn during sleep.

Nasal CPAP therapy is highly effective to treat certain respiratorydisorders, provided patients comply with therapy. If a mask isuncomfortable, or difficult to use a patient may not comply withtherapy. Since it is often recommended that a patient regularly washtheir mask, if a mask is difficult to clean (e.g. difficult to assembleor disassemble), patients may not clean their mask and this may impacton patient compliance.

While a mask for other applications (e.g. aviators) may not be suitablefor use in treating sleep disordered breathing, a mask designed for usein treating sleep disordered breathing may be suitable for otherapplications.

For these reasons, masks for delivery of nasal CPAP during sleep form adistinct field.

Seal-Forming Portion

Patient interfaces may include a seal-forming portion. Since it is indirect contact with the patient's face, the shape and configuration ofthe seal-forming portion can have a direct impact the effectiveness andcomfort of the patient interface.

A patient interface may be partly characterised according to the designintent of where the seal-forming portion is to engage with the face inuse. In one form of patient interface, a seal-forming portion maycomprise two sub-portions to engage with respective left and rightnares. In one form of patient interface, a seal-forming portion maycomprise a single element that surrounds both nares in use. Such singleelement may be designed to for example overlay an upper lip region and anasal bridge region of a face. In one form of patient interface aseal-forming portion may comprise an element that surrounds a mouthregion in use, e.g. by forming a seal on a lower lip region of a face.In one form of patient interface, a seal-forming portion may comprise asingle element that surrounds both nares and a mouth region in use.These different types of patient interfaces may be known by a variety ofnames by their manufacturer including nasal masks, full-face masks,nasal pillows, nasal puffs and oro-nasal masks.

A seal-forming portion that may be effective in one region of apatient's face may be in appropriate in another region, e.g. because ofthe different shape, structure, variability and sensitivity regions ofthe patient's face. For example, a seal on swimming goggles thatoverlays a patient's forehead may not be appropriate to use on apatient's nose.

Certain seal-forming portions may be designed for mass manufacture suchthat one design fit and be comfortable and effective for a wide range ofdifferent face shapes and sizes. To the extent to which there is amismatch between the shape of the patient's face, and the seal-formingportion of the mass-manufactured patient interface, one or both mustadapt in order for a seal to form.

One type of seal-forming portion extends around the periphery of thepatient interface, and is intended to seal against the user's face whenforce is applied to the patient interface with the seal-forming portionin confronting engagement with the user's face. The seal-forming portionmay include an air or fluid filled cushion, or a moulded or formedsurface of a resilient seal element made of an elastomer such as arubber. With this type of seal-forming portion, if the fit is notadequate, there will be gaps between the seal-forming portion and theface, and additional force will be required to force the patientinterface against the face in order to achieve a seal.

Another type of seal-forming portion incorporates a flap seal of thinmaterial so positioned about the periphery of the mask so as to providea self-sealing action against the face of the user when positivepressure is applied within the mask. Like the previous style of sealforming portion, if the match between the face and the mask is not good,additional force may be required to effect a seal, or the mask may leak.Furthermore, if the shape of the seal-forming portion does not matchthat of the patient, it may crease or buckle in use, giving rise toleaks.

Another type of seal-forming portion may comprise a friction-fitelement, e.g. for insertion into a naris.

Another form of seal-forming portion may use adhesive to effect a seal.Some patients may find it inconvenient to constantly apply and remove anadhesive to their face.

A range of patient interface seal-forming portion technologies aredisclosed in the following patent applications, assigned to ResMedLimited: WO 1998/004,310; WO 2006/074,513; WO 2010/135,785.

One form of nasal pillow is found in the Adam Circuit manufactured byPuritan Bennett. Another nasal pillow, or nasal puff is the subject ofU.S. Pat. No. 4,782,832 (Trimble et al.), assigned to Puritan-BennettCorporation.

ResMed Limited has manufactured the following products that incorporatenasal pillows: SWIFT nasal pillows mask, SWIFT II nasal pillows mask,SWIFT LT nasal pillows mask, SWIFT FX nasal pillows mask and LIBERTYfull-face mask. The following patent applications, assigned to ResMedLimited, describe nasal pillows masks: International Patent ApplicationWO2004/073,778 (describing amongst other things aspects of ResMed SWIFTnasal pillows), US Patent Application 2009/0044808 (describing amongstother things aspects of ResMed SWIFT LT nasal pillows); InternationalPatent Applications WO 2005/063,328 and WO 2006/130,903 (describingamongst other things aspects of ResMed LIBERTY full-face mask);International Patent Application WO 2009/052,560 (describing amongstother things aspects of ResMed SWIFT FX nasal pillows).

Positioning and Stabilising

A seal-forming portion of a patient interface used for positive airpressure therapy is subject to the corresponding force of the airpressure to disrupt a seal. Thus a variety of techniques have been usedto position the seal-forming portion, and to maintain it in sealingrelation with the appropriate portion of the face.

One technique is the use of adhesives. See for example US Patentpublication US 2010/0000534.

Another technique is the use of one or more straps and stabilisingharnesses. Many such harnesses suffer from being one or more ofill-fitting, bulky, uncomfortable and awkward to use.

Vent Technologies

Some forms of patient interface systems may include a vent to allow thewashout of exhaled carbon dioxide. Many such vents are noisy. Others mayblock in use and provide insufficient washout. Some vents may bedisruptive of the sleep of a bed-partner 1100 of the patient 1000, e.g.through noise or focussed airflow.

ResMed Limited has developed a number of improved mask venttechnologies. See WO 1998/034,665; WO 2000/078,381; U.S. Pat. No.6,581,594; US patent application; US 2009/0050156; US Patent Application2009/0044808.

Table of noise of prior masks (ISO 17510-2: 2007, 10 cmH₂O pressure at 1m) A-weighted A-weighted sound power sound level dbA pressure dbA YearMask name Mask type (uncertainty) (uncertainty) (approx.) Glue-on (*)nasal 50.9 42.9 1981 ResCare nasal 31.5 23.5 1993 standard (*) ResMednasal 29.5 21.5 1998 Mirage (*) ResMed nasal 36 (3) 28 (3) 2000UltraMirage ResMed nasal 32 (3) 24 (3) 2002 Mirage Activa ResMed nasal30 (3) 22 (3) 2008 Mirage Micro ResMed nasal 29 (3) 22 (3) 2008 MirageSoftGel ResMed nasal 26 (3) 18 (3) 2010 Mirage FX ResMed nasal 37   29  2004 Mirage pillows Swift (*) ResMed nasal 28 (3) 20 (3) 2005 Miragepillows Swift II ResMed nasal 25 (3) 17 (3) 2008 Mirage Swift pillows LT((*)one specimen only, measured using test method specified in ISO3744in CPAP mode at 10 cmH₂O)

Sound pressure values of a variety of objects are listed below

A-weighted sound pressure dbA Object (uncertainty) Notes Vacuum cleaner:Nilfisk 68 ISO3744 at 1 m Walter Broadly Litter distance Hog: B+ GradeConversational speech 60 1 m distance Average home 50 Quiet library 40Quiet bedroom at night 30 Background in TV studio 20Respiratory Pressure Therapy (RPT) Device

One known RPT device used for treating sleep disordered breathing is theS9 Sleep Therapy System, manufactured by ResMed. Another example of anRPT device is a ventilator. Ventilators such as the ResMed Stellar™Series of Adult and Paediatric Ventilators may provide support forinvasive and non-invasive non-dependent ventilation for a range ofpatients for treating a number of conditions such as but not limited toNMD, OHS and COPD. RPT devices have also been known as flow generators.

The ResMed Elisée™ 150 ventilator and ResMed VS III™ ventilator mayprovide support for invasive and non-invasive dependent ventilationsuitable for adult or paediatric patients for treating a number ofconditions. These ventilators provide volumetric and barometricventilation modes with a single or double limb circuit.

RPT devices typically comprise a pressure generator, such as amotor-driven blower or a compressed gas reservoir, and are configured tosupply a flow of air to the airway of a patient. In some cases, the flowof air may be supplied to the airway of the patient at positivepressure. The outlet of the RPT device is connected via an air circuitto a patient interface such as those described above.

RPT devices typically also include an inlet filter, various sensors anda microprocessor-based controller. A blower may include aservo-controlled motor, a volute and an impeller. In some cases a brakefor the motor may be implemented to more rapidly reduce the speed of theblower so as to overcome the inertia of the motor and impeller. Thebraking can permit the blower to more rapidly achieve a lower pressurecondition in time for synchronization with expiration despite theinertia. In some cases the pressure generator may also include a valvecapable of discharging generated air to atmosphere as a means foraltering the pressure delivered to the patient as an alternative tomotor speed control. The sensors measure, amongst other things, motorspeed, mass flow rate and outlet pressure, such as with a pressuretransducer or the like. The controller may include data storage capacitywith or without integrated data retrieval and display functions.

Table of noise output levels of prior devices (one specimen only,measured using test method specified in ISO3744 in CPAP mode at 10cmH₂O). A-weighted sound power Device name level dB(A) Year (approx.)C-Series Tango 31.9 2007 C-Series Tango 33.1 2007 with Humidifier S8Escape II 30.5 2005 S8 Escape II with 31.1 2005 H4i Humidifier S9AutoSet 26.5 2010 S9 AutoSet with 28.6 2010 H5i HumidifierHumidifier

Delivery of a flow of breathable gas without humidification may causedrying of airways. Medical humidifiers are used to increase humidityand/or temperature of the flow of breathable gas in relation to ambientair when required, typically where the patient may be asleep or resting(e.g. at a hospital). As a result, a medical humidifier is preferablysmall for bedside placement, and it is preferably configured to onlyhumidify and/or heat the flow of breathable gas delivered to the patientwithout humidifying and/or heating the patient's surroundings.Room-based systems (e.g. a sauna, an air conditioner, an evaporativecooler), for example, may also humidify air that is breathed in by thepatient, however they would also humidify and/or heat the entire room,which may cause discomfort to the occupants.

The use of a humidifier with a flow generator or RPT device and thepatient interface produces humidified gas that minimizes drying of thenasal mucosa and increases patient airway comfort. In addition, incooler climates warm air applied generally to the face area in and aboutthe patient interface is more comfortable than cold air.

Respiratory humidifiers are available in many forms and may be astandalone device that is coupled to a respiratory apparatus via an aircircuit, is integrated with or configured to be coupled to the relevantrespiratory apparatus. While known passive humidifiers can provide somerelief, generally a heated humidifier may be used to provide sufficienthumidity and temperature to the air so that the patient will becomfortable. Humidifiers typically comprise a water reservoir or tubhaving a capacity of several hundred milliliters (ml), a heating elementfor heating the water in the reservoir, a control to enable the level ofhumidification to be varied, a gas inlet to receive gas from the flowgenerator or RPT device, and a gas outlet adapted to be connected to anair circuit that delivers the humidified gas to the patient interface.

Heated passover humidification is one common form of humidification usedwith a RPT device. In such humidifiers the heating element may beincorporated in a heater plate which sits under, and is in thermalcontact with, the water tub. Thus, heat is transferred from the heaterplate to the water reservoir primarily by conduction. The air flow fromthe RPT device passes over the heated water in the water tub resultingin water vapour being taken up by the air flow. The ResMed H4i™ and H5i™Humidifiers are examples of such heated passover humidifiers that areused in combination with ResMed S8 and S9 CPAP devices respectively.

Other humidifiers may also be used such as a bubble or diffuserhumidifier, a jet humidifier or a wicking humidifier. In a bubble ordiffuser humidifier the air is conducted below the surface of the waterand allowed to bubble back to the top. A jet humidifier produces anaerosol of water and baffles or filters may be used so that theparticles are either removed or evaporated before leaving thehumidifier. A wicking humidifier uses a water absorbing material, suchas sponge or paper, to absorb water by capillary action. The waterabsorbing material is placed within or adjacent at least a portion ofthe air flow path to allow evaporation of the water in the absorbingmaterial to be taken up into the air flow.

An alternative form of humidification is provided by the ResMedHumiCare™ D900 humidifier that uses a CounterStream™ technology thatdirects the air flow over a large surface area in a first directionwhilst supplying heated water to the large surface area in a secondopposite direction. The ResMed HumiCare™ D900 humidifier may be usedwith a range of invasive and non-invasive ventilators.

BRIEF SUMMARY OF THE TECHNOLOGY

The present technology relates to devices that may be used medicallysuch as for the diagnosis, amelioration, treatment, and/or prevention ofrespiratory disorders, and may have one or more features for improvedcomfort, cost, efficacy, ease of use and/or manufacturability.

A first aspect of the present technology relates to apparatus used inthe diagnosis, amelioration, treatment or prevention of a respiratorydisorder.

Another aspect of the present technology relates to methods used in thediagnosis, amelioration, treatment or prevention of a respiratorydisorder.

One form of the present technology includes a vent, the vent may beconfigurable with a variable aperture size for communicating a flow ofbreathable gas. Another aspect of the present technology involves thefeatures of a vent such that the cross section profile exposed to theflow of breathable gas traversing through the vent remains constant evenas the vent aperture size changes.

Another form of the present technology comprises a vent arrangementcomprising a plurality of vents. Another key aspect of this form of thepresent technology is that the aperture size of each vent may becontrolled independently or together. Furthermore, the aperture size ofeach vent may be controlled according to one or more input signals fromone or more sensors, suitable examples of the one or more sensors mayinclude flow, pressure, noise, accelerometer outputs, orientation of apatient or presence of any obstructions.

Another aspect of one form of the present technology is the control ofsize of cross-section areas of a plurality of vents according to one ormore input signals from one or more sensors. Examples of suitable inputsignals include flow, pressure, noise, accelerometer outputs,orientation of a patient or presence of any obstructions.

Another aspect of one form of the present technology is a ventarrangement comprising a plurality of vents, and a plurality ofmicrophones, each vent comprising a variable cross-section area forcommunication of a flow of breathable to gas and the microphonesconfigured to produce signals indicating the noise level generated by aflow of breathable gas communicating through each vent, wherein thecross-section area of each vent is controlled according to the signalsproduced by the microphones.

Another aspect of one form of the present technology is a ventarrangement comprising a plurality of vents and an accelerometer, eachvent comprising a variable cross-section area for communication of aflow of breathable gas and the accelerometer configured to produce asignal indicating orientation of the patient or the orientation of thevent arrangement, wherein the cross-section area of each vent iscontrolled according to the signal produced by the accelerometer.

Another aspect of one form of the present technology is a ventarrangement comprising a plurality of vents, each vent comprising avariable cross-section area for communication of a flow of breathablegas, wherein the cross-section area of each vent is controlled accordingto an output from a pressure sensor, wherein the pressure sensor ismeasuring a pressure of the flow of breathable gas delivered to thepatient.

Another aspect of one form of the present technology is a ventarrangement comprising a plurality of vents, each vent comprising avariable cross-section area for communication of a flow of breathablegas, wherein the cross-section area of each vent is controlled accordingto an output from a flow sensor, wherein the flow sensor is measuring aflow rate of the flow of breathable gas delivered to the patient.

Another aspect of one form of the present technology is a ventarrangement comprising a plurality of vents, each vent comprising avariable cross-section area for communication of a flow of breathablegas, wherein the cross-section area of each vent is controlled accordingto an aspect of the patient's breath waveform.

A yet another aspect of the current technology is a patient interfacecomprising a vent arrangement.

A yet another aspect of the current technology is an air circuitcomprising a vent arrangement.

A yet another aspect of the current technology is a vent arrangementconfigured to couple with an air circuit or a patient interface.

Some versions of the present technology include a gas washout ventarrangement for exhausting a flow of exhaust gas received within apatient interface. The gas washout vent arrangement may include one ormore vents to exhaust a flow of exhaust gas received within a patientinterface, the one or more vents adapted to provide a plurality ofdifferent venting configurations. It may further include a sensoradapted to generate a signal indicative of disruption attributable tothe exhaust gas. The one or more vents are adjustable to one of theplurality of different venting configurations based on the signal.

In some cases, the one or more vents may be configured for continuousadjustment while the patient interface is in use. The one or more ventsmay adjust to vary direction of the flow of exhausted gas. The one ormore vents may adjust to vary velocity of the flow of exhausted gas. Insome cases, the signal may be based on a measured noise level. Thesignal may be based on detected orientation of the patient interface.

In some examples, the one or more vents may adjust to vary one or moreflow impedances of the one or more vents. The one or more vents mayadjust by actuating movement of a movable portion of the one or morevents. In some examples, at least a portion of the gas washout ventarrangement may be located in a patient interface. At least a portion ofthe gas washout vent arrangement may be located in an air circuit. Atleast a portion of the gas washout vent arrangement may be located in ashell of the patient interface. At least a portion of the gas washoutvent arrangement may be located in a decoupling structure of the patientinterface. At least a portion of the gas washout vent arrangement may bestructured to be coupled with the patient interface.

In some examples, the gas washout vent arrangement may include acontroller, such as a processor. The controller may be configured toselectively adjust the vent arrangement based on a detected vent noiseto increase an exhaust area of a first vent and decrease an exhaust areaof a second vent. The controller may be configured to selectively adjustthe vent arrangement based on a detected orientation of the patientinterface to increase an exhaust area of a first vent and decrease anexhaust area of a second vent.

The present technology may include apparatus for treating a respiratorydisorder. The apparatus may include a patient interface for delivering asupply of air or breathable gas to the entrance of a patient's airways.The apparatus may also include a flow generator for supplying the supplyof air or breathable gas to the patient interface. The apparatus mayalso include a gas washout vent arrangement such as any of thearrangements previously described or described in more detail hereafter.The apparatus may include a controller configured to receive the signalfrom the sensor and generate one or more signals to adjust the one ormore vents in response to the signal indicative of disruption.

Some versions of the present technology may include a control method,such as a control method of an apparatus for adjusting a flow of exhaustgas from a patient interface. The control method may include generatingwith a sensor a signal indicative of disruption attributable to a flowof exhaust gas through one or more vents from a patient interface. Theone or more vents may be adapted for a plurality of different ventingconfigurations. The control method may further include adjusting with acontroller the one or more vents to one of the plurality of differentventing configurations based on the signal, whereby disruption to a userand/or bed-partner of the user may be reduced.

In some cases of the method, the one or more vents may be adapted forcontinuous adjustment while the patient interface is in use. Theadjusting of the one or more vents to one of the plurality of differentventing configurations may change a characteristic of the flow ofexhaust gas. The characteristic may be direction of the flow ofexhausted gas. The characteristic may be velocity of the flow ofexhausted gas. In some cases, the signal may be generated based on ameasured noise level. In some cases, the signal maybe generated based ondetected orientation of the patient interface. The adjusting the one ormore vents to one of the plurality of different venting configurationsmay include actuating movement of a movable portion of the one or morevents. In some cases, the controller may selectively adjust the one ormore vents based on detected vent noise to increase an exhaust area of afirst vent and decrease an exhaust area of a second vent. The controllermay selectively adjust the one or more vents based on detectedorientation of the patient interface to increase an exhaust area of afirst vent and decrease an exhaust area of a second vent.

Some embodiments of the present technology may include an apparatus,such as a patient interface, for applying or delivering a flow ofbreathable gas to an airway of user. The apparatus may include a plenumchamber adapted for coupling with a flow generator or respiratorypressure therapy device to a supply breathable gas to the plenumchamber. The plenum chamber may be further adapted to couple with anairway of a user. The apparatus may also include one or more exhaustvents. The exhaust vents may be coupled with the plenum chamber topermit a flow of exhaust gas from a cavity of the plenum chamber. Theone or more exhaust vents may be configured to change a direction ofexhaust flow relative to the plenum chamber in accordance withorientation of the plenum chamber such as a change in orientation of theplenum chamber.

The one or more exhaust vents may be configured to enforce an upwardflow of exhaust from the plenum chamber upon a changing orientation ofthe plenum chamber. The one or more exhaust vents may be configured toreduce an exhaust flow in a direction of a bed partner upon a changingorientation of the plenum chamber. The one or more exhaust vents mayinclude a plurality of apertures and a movable portion configured toselectively move between a first end and a second end according to agravitational orientation of the plenum chamber.

The apparatus may include an orientation sensor to detect or senseorientation of the plenum chamber, for example by generating a signalindicative of orientation of the plenum chamber, an actuator to adjustopening of the one or more exhaust vents, and/or a controller coupledwith the orientation sensor and actuator. The controller may beconfigured to control adjustment of the one or more exhaust vents inresponse to detected orientation of the plenum chamber such as inresponse to the signal indicative of orientation of the plenum chamber.The apparatus may include a sensor adapted to generate a signalindicative of disruption attributable to the exhaust gas, and the one ormore exhaust vents may be adjustable to one of a plurality of differentventing configurations based on the signal.

In some cases, the one or more exhaust vents may include a first exhaustvent and a second exhaust vent, the first exhaust vent and secondexhaust vent located on opposing sides of the plenum chamber to directexhaust flow in opposing directions. The plenum chamber may be coupledwith a mask frame. The plenum chamber may be coupled with headgear. Theplenum chamber may form part of a nasal mask. The plenum chamber mayform part of a mouth and nose mask. The plenum chamber may form part ofa nasal pillow.

The apparatus may further include the respiratory pressure therapydevice or flow generator and a respiratory pressure therapy devicecontroller or flow generator controller including a processor. The flowgenerator controller or respiratory pressure therapy device controllermay be configured to control adjustment of an opening of the one or moreexhaust vents.

In some cases, an exhaust vent of the one or more exhaust vents mayinclude a swivel having a vent aperture. An exhaust vent of the one ormore exhaust vents may include a guide channel having a sliding orrolling movable portion and a plurality of apertures. An exhaust vent ofthe one or more exhaust vents may include a set of movable leaves withan adjustable aperture central to the set of leaves. The one or morevents may be adjustable to increase an exhaust area of a first vent anddecrease an exhaust area of a second vent responsive to an orientationof the plenum chamber. In some cases, a controller may be configured toadjust the one or more vents based on a detected orientation of theplenum chamber to increase an exhaust area of a first vent and decreasean exhaust area of a second vent.

Of course, portions of the aspects may form sub-aspects of the presenttechnology. Also, various ones of the sub-aspects and/or aspects may becombined in various manners and also constitute additional aspects orsub-aspects of the present technology.

Other features of the technology will be apparent from consideration ofthe information contained in the following detailed description,abstract, drawings and claims.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

The present technology is illustrated by way of example, and not by wayof limitation, in the figures of the accompanying drawings, in whichlike reference numerals refer to similar elements including:

Treatment Systems

FIG. 1a shows a system in accordance with the present technology. Apatient 1000 wearing a patient interface 3000, in the form of nasalpillows, receives a supply of air at positive pressure from a RPT device4000. Air from the RPT device is humidified in a humidifier 5000, andpasses along an air circuit 4170 to the patient 1000.

FIG. 1b shows a system including a patient 1000 wearing a patientinterface 3000, in the form of a nasal mask, receives a supply of air atpositive pressure from a RPT device 4000. Air from the RPT device ishumidified in a humidifier 5000, and passes along an air circuit 4170 tothe patient 1000.

FIG. 1c shows a system including a patient 1000 wearing a patientinterface 3000, in the form of a full-face mask, receives a supply ofair at positive pressure from a RPT device. Air from the RPT device ishumidified in a humidifier 5000, and passes along an air circuit 4170 tothe patient 1000.

Therapy

Respiratory System

FIG. 2a shows an overview of a human respiratory system including thenasal and oral cavities, the larynx, vocal folds, oesophagus, trachea,bronchus, lung, alveolar sacs, heart and diaphragm.

FIG. 2b shows a view of a human upper airway including the nasal cavity,nasal bone, lateral nasal cartilage, greater alar cartilage, nostril,lip superior, lip inferior, larynx, hard palate, soft palate,oropharynx, tongue, epiglottis, vocal folds, oesophagus and trachea.

Facial Anatomy

FIG. 2c is a front view of a face with several features of surfaceanatomy identified including the lip superior, upper vermillion, lowervermillion, lip inferior, mouth width, endocanthion, a nasal ala,nasolabial sulcus and cheilion.

Patient Interface

FIG. 3a shows an example of a patient interface known in the prior art.

Respiratory Pressure Therapy (RPT) Device

FIG. 4a shows a RPT device in accordance with one form of the presenttechnology.

FIG. 4b shows a schematic diagram of the pneumatic circuit of a RPTdevice in accordance with one form of the present technology. Thedirections of upstream and downstream are indicated.

FIG. 4c shows a schematic diagram of the electrical components of a RPTdevice in accordance with one aspect of the present technology.

Humidifier

FIG. 5a shows a humidifier in accordance with one aspect of the presenttechnology.

Breathing Waveforms

FIG. 6a shows a model typical breath waveform of a person whilesleeping, the horizontal axis is time, and the vertical axis isrespiratory flow. While the parameter values may vary, a typical breathmay have the following approximate values: tidal volume, Vt, 0.5 L,inhalation time, Ti, 1.6 s, peak inspiratory flow, Qpeak, 0.4 L/s,exhalation time, Te, 2.4 s, peak expiratory flow, Qpeak, −0.5 L/s. Thetotal duration of the breath, Ttot, is about 4 s. The person typicallybreathes at a rate of about 15 breaths per minute (BPM), withVentilation, Vent, about 7.5 L/s. A typical duty cycle, the ratio of Tito Ttot is about 40%.

Gas Washout Vent Arrangements

FIG. 7-8 show front views of one form of a vent according to the currenttechnology. FIG. 7 shows a configuration of the vent where theadjustable vent aperture 3422 is closed, and FIG. 8 shows anotherconfiguration where the adjustable vent aperture 3422 has been enlarged.

FIG. 9-11 show exploded perspective views of one form of a ventaccording to the current technology. FIG. 9 shows a configuration of thevent where the vent aperture 3422 is closed, FIG. 10 shows anotherconfiguration where the vent aperture 3422 has been enlarged and FIG. 11shows another configuration where the vent aperture 3422 has beenenlarged further.

FIG. 12a-12b show rear perspective views of one form of a vent accordingto the current technology. FIG. 12a shows a configuration of the ventwhere the vent aperture 3422 is closed, and FIG. 12b shows anotherconfiguration where the vent aperture 3422 has been enlarged.

FIG. 13 shows an exploded rear perspective view of some components of avent according to the current technology.

FIG. 14a-14b show front perspective views of components of a ventaccording to the current technology, showing the leaves 3404. FIG. 14ashows a configuration of the leaves 3404 where the vent aperture 3422 ispartially closed, and FIG. 14b shows another configuration where thevent aperture 3422 has been enlarged.

FIG. 15 shows a rear perspective view of one form of a leaf 3404according to the current technology.

FIG. 16A shows a front view of one form of a leaf 3404 according to thecurrent technology, with FIG. 16B showing a cross-sectional view of theleaf 3404 taken along line A-A of FIG. 16A.

FIG. 17 shows a flow chart of one form of a vent aperture size controlmethodology of the current technology.

FIG. 18 shows a flow chart of one form of a vent aperture size controlmethodology of the current technology wherein a plurality of vents areused as well as a plurality of noise levels.

FIG. 19 shows a flow chart of one form of a vent aperture size controlmethodology of the current technology wherein a plurality of vents areused as well as a plurality of noise levels and a threshold noise level.

FIG. 20 shows a flow chart of one form of a vent aperture size controlmethodology of the current technology wherein the orientation of thepatient is used.

FIG. 21 shows a flow chart of one form of a vent aperture size controlmethodology of the current technology wherein a plurality of vents areused as well as a plurality of noise levels, a threshold noise level anda lookup table.

FIG. 22 shows a front view of one form of a patient interface 3000according to the current technology, including a plurality of vents 3400and sensors such as microphones 3440, proximity sensors 3444 andaccelerometer(s) 3442.

FIG. 23a shows a flow chart of one form of a vent actuator calibrationmethodology of the current technology wherein the ‘completely open’position is recorded.

FIG. 23b shows a flow chart of one form of a vent actuator calibrationmethodology of the current technology wherein the ‘completely closed’position is recorded.

FIG. 24 shows a front view of one form of some components of a ventaccording to the current technology, particularly showing the leaves3404, such as leaves 3404(a) and 3404(b).

FIG. 25 is a graph of sound power levels according to one form of a ventaccording to the current technology, showing the comparative sound powerlevels according to various therapy pressures and opening sizes.

FIG. 26a-26b show front views of one form of a patient interface 3000according to the current technology, including a vent 3400 with amovable portion 3456.

FIG. 27a-27b show front views of another form of a patient interface3000 according to the current technology, including a vent 3400 with amovable portion 3456.

FIG. 28a-28b show front views of a yet another form of a patientinterface 3000 according to the current technology, including a vent3400 with a movable portion 3456 which is adapted to move, such asaccording to gravity, in a guiding portion 3458.

FIG. 29 shows a patient 1000 lying on a bed wearing a patient interface3000 according to an aspect of the present technology, wherein patientinterface 3000 includes a movable portion 3456.

FIGS. 30a-30b show front views of a yet another form of a patientinterface 3000 according to the current technology, including a vent3400 with a movable portion 3456, such as one which is adapted to rotateto vary the direction of the aperture 3457.

DETAILED DESCRIPTION OF EXAMPLES OF THE TECHNOLOGY

Before the present technology is described in further detail, it is tobe understood that the technology is not limited to the particularexamples described herein, which may vary. It is also to be understoodthat the terminology used in this disclosure is for the purpose ofdescribing only the particular examples discussed herein, and is notintended to be limiting.

Treatment Systems

In one form, the present technology comprises apparatus for treating arespiratory disorder. The apparatus may comprise a flow generator orblower for supplying pressurised respiratory gas, such as air, to thepatient 1000 via an air delivery tube leading to a patient interface3000.

Therapy

In one form, the present technology comprises a method for treating arespiratory disorder comprising the step of applying positive pressureto the entrance of the airways of a patient 1000.

Nasal CPAP for OSA

In one form, the present technology comprises a method of treatingObstructive Sleep Apnea in a patient by applying nasal continuouspositive airway pressure to the patient.

Patient Interface 3000

A non-invasive patient interface 3000 in accordance with one aspect ofthe present technology comprises the following functional aspects: aseal-forming structure 3100, a plenum chamber 3200, a positioning andstabilising structure 3300, a vent 3400 and a connection port 3600 forconnection to air circuit 4170. In some forms a functional aspect may beprovided by one or more physical components. In some forms, one physicalcomponent may provide one or more functional aspects. In use theseal-forming structure 3100 is arranged to surround an entrance to theairways of the patient so as to facilitate the supply of air at positivepressure to the airways.

Seal-Forming Structure 3100

In one form of the present technology, a seal-forming structure 3100provides a sealing-forming surface, and may additionally provide acushioning function.

A seal-forming structure 3100 in accordance with the present technologymay be constructed from a soft, flexible, resilient material such assilicone.

In one form, the seal-forming structure 3100 comprises a sealing flangeand a support flange. Preferably the sealing flange comprises arelatively thin member with a thickness of less than about 1 mm, forexample about 0.25 mm to about 0.45 mm, that extends around theperimeter 3210 of the plenum chamber 3200. Support flange may berelatively thicker than the sealing flange. The support flange isdisposed between the sealing flange and the marginal edge of the plenumchamber 3200, and extends at least part of the way around the perimeter3210. The support flange is or includes a spring-like element andfunctions to support the sealing flange from buckling in use. In use thesealing flange can readily respond to system pressure in the plenumchamber 3200 acting on its underside to urge it into tight sealingengagement with the face.

In one form the seal-forming portion of the non-invasive patientinterface 3000 comprises a pair of nasal puffs, or nasal pillows, eachnasal puff or nasal pillow being constructed and arranged to form a sealwith a respective naris of the nose of a patient.

Nasal pillows in accordance with an aspect of the present technologyinclude: a frusto-cone, at least a portion of which forms a seal on anunderside of the patient's nose; a stalk, a flexible region on theunderside of the cone and connecting the cone to the stalk. In addition,the structure to which the nasal pillow of the present technology isconnected includes a flexible region adjacent the base of the stalk. Theflexible regions can act in concert to facilitate a universal jointstructure that is accommodating of relative movement—both displacementand angular—of the frusto-cone and the structure to which the nasalpillow is connected. For example, the frusto-cone may be axiallydisplaced towards the structure to which the stalk is connected.

In one form the non-invasive patient interface 3000 comprises aseal-forming portion that forms a seal in use on an upper lip region(that is, the lip superior) of the patient's face.

In one form the non-invasive patient interface 3000 comprises aseal-forming portion that forms a seal in use on a chin-region of thepatient's face.

Plenum Chamber 3200

Preferably the plenum chamber 3200 has a perimeter 3210 that is shapedto be complementary to the surface contour of the face of an averageperson in the region where a seal will form in use. In use, a marginaledge of the plenum chamber 3200 is positioned in close proximity to anadjacent surface of the face. Actual contact with the face is providedby the seal-forming structure 3100. Preferably the seal-formingstructure 3100 extends in use about the entire perimeter 3210 of theplenum chamber 3200.

In one form, the plenum chamber 3200 may surround and/or be in fluidcommunication with the nares of the patient where the plenum chamber3200 is a part of a nasal mask (e.g. shown in FIG. 1b ). In anotherform, the plenum chamber 3200 may surround and/or be in fluidcommunication with the nares and the mouth of the patient where theplenum chamber 3200 is a part of a full-face mask (e.g., shown in FIG.1c ). In yet another form, the plenum chamber 3200 may engage and/or bein fluid communication with one or more of the nares of the patientwhere the plenum chamber 3200 is a part of nasal pillows (e.g., shown inFIG. 29).

Positioning and Stabilising Structure 3300

Preferably the seal-forming structure 3100 of the patient interface 3000of the present technology is held in sealing position in use by thepositioning and stabilising structure 3300.

Vent 3400

In one form, the patient interface 3000 includes a vent 3400 constructedand arranged to allow for the washout of exhaled carbon dioxide or anyother exhaust gas from the patient interface 3000.

One form of vent 3400 known in the prior art comprises a plurality ofholes, for example, about 20 to about 80 holes, or about 40 to about 60holes, or about 45 to about 55 holes.

The vent 3400 may be located in or on the surface/barrier/shell of theplenum chamber 3200. Alternatively, or in addition thereto, the vent3400 may be located in a decoupling structure, e.g. a swivel 3510 (seeFIG. 29) or a ball and socket 3520 (see FIG. 27a ).

A vent arrangement, comprising one or a plurality of vents 3400 asdescribed below may be located in the patient interface 3000, in the aircircuit 4170 or as a separate component configured to be coupled to apatient interface 3000 or an air circuit 4170.

An exemplary gas washout vent 3400 according to an aspect of the currenttechnology is shown in FIG. 7, showing a single vent 3400 whichcomprises a plurality of blades, or leaves 3404 and an outer housing3408.

The vent 3400 may allow for a flow of breathable gas to traverse betweeneither sides of the vent 3400 via a vent aperture 3422 as shown in FIG.8. One aspect of the current technology is that the size of a ventaperture 3422 of a vent 3400 may be adjusted between a maximum size anda minimum size, allowing a plurality of configurations for the gaswashout vent arrangement. Thus, aspects of the air flow therethrough maybe adjusted and/or controlled by changing the size of the vent aperture3422.

Aspects of the air flow through the vent 3400 may be modified bychanging properties of the vent 3400, such as the size and/ororientation of the vent aperture 3422 or the components thereof.Examples of aspects of the air flow through the vent 3400 that may bemodified by changing properties of the vent 3400 (such as the size ofthe vent aperture 3422) include the air impedance, or flow impedance, ofthe vent 3400 and/or characteristics of noise generated by the air flowas it flows through the vent 3400. For instance, the velocity of theflow of exhaust gas that is exhausted through the gas washout ventarrangement may be varied by varying the air impedance of the vent 3400.By varying the orientation of the components defining the vent aperture3422, a direction of the air flow may be varied.

Vent Geometry

The size of the vent aperture 3422 may be described using a distance‘across faces’, which is the distance across the aperture between theopposing faces of leaves 3404. An example of this measurement is shownin FIG. 24, wherein the distance designated D_(AF) between a face of aleaf 3404(a) and a face of the opposing leaf 3404(b) would be a distance‘across faces. However, any number of other metrics may be used todescribe the geometry. It is noted that although the faces of the leaves3404 are shown as flat in FIG. 24, the face or surface of a leaf 3404does not have to be flat and may have an alternative profile such ascurved, jagged or tooth-shaped.

FIG. 9 shows an exploded view of the exemplary vent 3400 with aplurality of leaves 3404, a guiding member, or guide ring 3406, and anouter housing 3408. As illustrated, the vent 3400 may include six leaves3404. However the vent may have any number of leaves 3404 as discussedin more detail below. The vent 3400 also may be connected to anactuating drive mechanism, which may include, for example, a magnet ring3452 and a coil 3454. The actuating drive mechanism may take the form ofany number of rotary or linear drive mechanisms, such as a linearactuator, a rotary actuator, a motor drive mechanism or any number ofsuch means known in the art. The actuating drive mechanism may includethe drive mechanism described in U.S. patent application Ser. No.13/967,609 filed on 15 Aug. 2013 or PCT/US2012/055148 filed on 13 Sep.2012, the contents of which are incorporated herein in its entirety.

FIGS. 10-11 show further exploded views of the vent 3400 similar to thatshown in FIG. 9, however showing different sizes of the vent aperture3422. FIGS. 9-11 also show that each leaf 3404 can be coupled with theguide ring 3406, in that the guide ring 3406 is shown to have rotated asthe vent aperture 3422 has changed in size. That is, partial rotation ofthe guide ring when coupled with the leaves will adjust the size of theopening of the vent aperture 3422. For example, in one direction,partial rotation of the guide ring will increase the opening in size andin the opposite direction, partial rotation of the guide ring willdecrease the opening in size.

The guide ring 3406 includes a plurality of guide ring keys 3410 formedon the outer surface of the guide ring 3406 that are configured to eachengage with a leaf guide slot 3412 (seen in FIG. 12a ) formed on a firstsurface of each of the plurality of leaves 3404. A second surface ofeach of the plurality of leaves, such as an opposing surface to thefirst surface, is configured to couple to the outer housing 3408. Eachof the plurality of leaves 3404 includes a leaf key 3414 located on asurface (such as the second surface) of each leaf 3404. Each leaf key3414 may be inserted into an outer housing guide slot 3416, which may bea hexagonally edged slot or a slot with a number of edges correspondingto the number of leaves, formed in the outer housing 3408 as shown inFIG. 13. In some configurations as shown in FIG. 13 the leaf guide slots3412 may be formed integrally with leaf keys 3414 such that the leafguide slots 3412 are on a first surface and the leaf keys are on anopposing second surface. Alternatively (not shown) the leaf guide slots3412 and the leaf keys 3414 may be on the same or adjacent surfaces.

FIGS. 12a-12b show a portion of the vent 3400 from a different angle tothat of FIGS. 9-11, showing the plurality of leaves 3404 and the outerhousing 3408 assembled together. These figures show the leaf guide slots3412 that are formed on the first surface of each leaf 3404. Each leafguide slot 3412 is configured to receive a guide ring key 3410 asdescribed above.

FIG. 13 shows an exploded view of the vent 3400, only showing theplurality of leaves 3404 and the outer housing 3408 to display the outerhousing guide slot 3416. It can be seen here that in this form, amovement of each individual leaf such as leaf 3404(3) follows a linearpath (shown by the double ended arrow in FIG. 13) in the outer housingguide slot 3416 into which the leaf key 3414 (as shown FIG. 14a ) isinserted along the edge of the slot. The outer housing guide slot 3416is shown in FIG. 13 as a single continuous recess formed integrally withthe outer housing 3408. However it may be formed as a plurality ofdiscrete recesses, each configured to receive a leaf key 3414, and/or asa discrete component coupled to the outer housing 3408.

FIGS. 14a and 14b show the plurality of leaves 3404 (or a leave set)arranged to form an adjustable vent aperture 4322 according to one formof the current technology, showing two different sizes of the ventaperture 3422. FIG. 14b also illustrates a direction of exhaust flow atarrow EF through the leaves. FIG. 15 shows an example of one of theplurality of leaves according to an example of the present technology.In this example, the leaf key 3414 is integrally formed as a part of theleaf 3404, however it should be understood that it may alternatively beformed as a separate component that may be coupled between each of theplurality of leaves 3404 and the outer housing 3408.

As the plurality of leaves 3404 are moved from a configuration shown inFIG. 14a to a configuration shown in FIG. 14b , an outer leaf surface3418 of one of the plurality of leaves 3404(1) slides relative to aninner leaf surface 3420 of an adjacent leaf 3404(2) of the plurality ofleaves such as in a tongue and groove fashion. In this form, thecoordinated movement of the plurality of leaves such as that between aleaf 3404(1) against an adjacent leaf 3404(2) result in the opening andclosing of the vent aperture 3422 while maintaining a seal between theplurality of leaves 3404 other than in the area of the open ventaperture 3422.

Another aspect of the current technology is that it may allow for thevent aperture 3422 to be adjusted between a maximum size and a minimumsize (e.g., limits). The maximum size and/or the minimum size may bepredetermined in some cases, although the maximum and/or the minimum maybe changed in other cases, for example to suit therapeutic need of eachpatient 100. The maximum size and/or the minimum size may be determinedby the geometry of the vent 3400, or be otherwise determined or set suchas by programming, or by adjustable switches for instance.

The predetermined minimum may be a zero area, or it may be a small areaor any other value for the area, as will be described in more detailbelow. Another aspect of this technology is that the size of the ventaperture 3422 may be infinitely adjustable between the maximum andminimum sizes, subject to the resolution of the controller and/or theactuation/adjustment mechanism. In other cases, the vent 3400 may bearranged so that the size of the vent aperture 3422 may be one of adiscrete number of sizes such as two, five, ten, fifteen or twenty forexample.

A number of leaves 3404 may be used to construct the vent 3400.Accordingly, shape of the leaves 3404, shape of the outer housing guideslot 3416 and the shape of the aperture 3422 may be dependent on thenumber of leaves 3404 used in the vent 3400. For instance, the ventaperture 3422 shown in FIG. 14b is in a hexagonal shape as the vent 3400has six leaves 3404 in this configuration. Preferably between three andeight leaves 3404 may be used in the vent 3400, more preferably betweenfour and six leaves 3404 may be used, although the number of leaves 3404may vary as the design parameters and requirements vary, such as thesize of the required aperture, material employed or the cross-sectionprofile of the leaf 3404.

In this arrangement of the current technology, each leaf guide slot 3412is shaped as a rectangular slot with rounded internal corners. Thisfacilitates slidable and rotatable movement of the corresponding guidering key 3410 within each leaf guide slot 3412 when the plurality ofleaves 3404 are moved to adjust the size of the vent aperture 3422. Inthis arrangement, the guide ring keys 3410 form a protrusion on theguide ring 3406 that is inserted into the leaf guide slots 3412 on eachof the plurality of leaves 3404.

It will be understood that any number of other mechanisms known in theart may be used to perform in a similar manner to the couplings shown inthe figures and/or described in this document. In an alternativearrangement, each of the plurality of leaves 3404 may include aprotrusion or key (not shown) and the guide ring 3406 may include a slotor recess (not shown) that enables the slidable and rotatable movementof the protrusion or key located on each of the plurality of leaves 3404as the plurality of leaves move. In a further alternative arrangementboth of the guide ring 3406 and each of the plurality of leaves 3404 mayinclude a slot or recess and a separate key component may be coupledtherebetween. In a yet further alternative, both of the guide ring 3406and each of the plurality of leaves 3404 may include protrusions or keysand a separate component comprising corresponding recesses or slots maybe coupled therebetween.

In one form, each of the plurality of leaves 3404 comprises a leaf key3414 on its second surface. The leaf key 3414 may have a shape withrounded internal corners to facilitate slidable movement of each of theplurality of leaves 3404 relative to the outer housing 3408, althoughany number of other arrangements may be used to perform in a similarmanner. As described above, the outer housing 3408 includes an outerhousing guide slot 3416 configured to receive the leaf keys 3414 fromone of the plurality of leaves 3404 therein. The outer housing guideslot 3416 is larger than the size of the leaf keys 3414 to facilitatemovement of the connecting plate protrusions along the outer housingguide slot 3416 when the plurality of leaves 3404 are moved to adjustthe size of the vent aperture 3422.

In an alternative arrangement, the outer housing 3408 may comprise keysand each of the plurality of leaves may include a slot or recess thatenables the slidable movement of the keys located on the outer housing3408 within the slots or recesses on the plurality of leaves 3404 as theplurality of leaves 3404 move. In a further alternative arrangement bothof the outer housing 3408 and each of the plurality of leaves 3404 mayinclude a slot or recess and a separate connecting plate component maybe coupled therebetween. In a yet another alternative arrangement bothof the outer housing 3408 and each of the plurality of leaves 3404 mayinclude keys and a separate connecting component comprising recesses orslots may be coupled therebetween.

Vent Controller

In another aspect of the present technology, a controller, such as onewith a processor(s) and which may optionally serve as a processor orcontroller of a RPT device, may be configured to control the one or morevents 3400 such as a vent arrangement described herein. In one form, thecontroller may be configured, e.g., programmed, to perform one or moreof the methods or algorithms described throughout this specification,such as to control aspects of the one or more vents 3400. For example,it may control the size and/or orientation of its apertures 3422. Suchcontrol may be, for example, based on one or more inputs as described infurther detail herein. Such a device controller or processor may, forexample, include integrated chips, such as application specificintegrated chip(s), a memory and/or other control instruction, data orinformation storage medium with the methodologies. Thus, programmedinstructions encompassing the methodologies may be coded on integratedchips or in the memory of the device. Such instructions may be loaded assoftware or firmware using an appropriate data storage medium. Thecontroller may then be in electrical communication with a controllableactuator or actuation mechanism as described herein for automatedmanipulation of the components of vent (e.g., guide ring and/or leaves).

In one form, a size of the vent aperture 3422 may be adjusted byrotationally constraining the outer housing 3408 and affixing the guidering 3406 to an actuator, which may be controlled by the controller. Theactuator may then rotate the guide ring 3406 to adjust the size of thevent aperture 3422. The controller may be configured to receive anindicative signal such as from the actuator and/or a discrete sensorregarding a property of the vent 3400, such as a signal indicating anorientation and/or the size of the aperture 3422. The actuator may befurther configured to determine when the size of the vent aperture 3422of the vent 3400 has reached the predetermined maximum or thepredetermined minimum throughout its range of possible sizes. In oneform, the actuator may include limit switches configured to detect whenthe vent aperture 3422 is at the minimum and/or the maximum size.

One aspect of the method of operation of the vent aperture controllermay be to control performing one or more calibration cycles with thevent 3400. According to one form of the calibration cycle, shown in FIG.23a , the first calibration cycle 34710 may be performed to determineone of the vent's limits, such as a ‘completely open’ position, or aposition of maximum size of the vent aperture 3422. In such a firstcalibration cycle 34710, the actuator 3480 may be instructed toprogressively open the vent 3400 in step 34712, while measuring thecurrent required in the actuator in step 34714 and comparing themeasured current (Imeas) in relation to a limit current (Timm) thresholdin step 34716. When the current limit is exceeded, the actuator may bestopped (step 34717) and the position may be recorded in step 34719.Thus, the first calibration cycle 34710 would continue until the size ofthe vent aperture 3422 reaches its maximum, upon which point thecontroller (using the limit switch for instance) may detect anindicative position signal such as the voltage supplied exceeding athreshold voltage, or the current supplied exceeding a thresholdcurrent, or the power supplied exceeding a threshold power, or aproximity sensor indicating that the vent is at its ‘completely open’position.

According to another form of the calibration cycle, shown in FIG. 23b ,the second calibration cycle 34720 may be performed to determine theother limit of the vent such as a ‘completely closed’ position, or aposition of minimum size of the vent aperture 3422. In the secondcalibration cycle 34720, the actuator 3480 may be instructed toprogressively close the vent 3400 in step 34722 until the aperture 3422reaches its minimum, upon which point the limit switch may detect anindicative position signal such as those described above (current,voltage and/or power). The first calibration cycle 34710 and the secondcalibration cycle 34720 may thus provide a controller with accuratelimits of travel for the leaves of the vent and thus the aperture 3422.Although these calibration cycles have been described in a particularorder, they may be reversed such that the first cycle may determine afully closed position and the second cycle may determine a fully openposition. Furthermore, a skilled addressee would understand that othercalibration steps to determine different positions of the leaves of thevent may also be undertaken.

Another aspect of the current technology is that the minimum size of thevent aperture 3422 may be so small so as to have zero area. Any numberof sizes may be chosen for the minimum size of the vent aperture 3422such as a size between, for example, 0.01 mm to 10 mm distance acrossfaces, such as 0.1 mm, 0.5 mm or 2 mm, 4 mm, 6 mm or 8 mm distanceacross faces.

According to another aspect of the present technology, the controllermay be in communication with one or more sensors and/or the ventarrangement to send and/or receive suitable control and/or sensingsignals. In some cases, the controller may be a central controller 4230that forms a part of the RPT device and performs other functions.However, the controller may optionally be a standalone vent controller3438 configured only to be in communication with the sensors and/or thevent arrangement. In some such cases, for example, the controller may beplaced on or in a patient interface or the air circuit. Such astandalone vent controller 3438 may optionally be in communication witha central controller 4230 as shown in FIG. 4c such as to be controlledby commands from the central controller.

Cross-Section Profile

As described above, some of the problems related to prior venttechnologies concern noise. Some may be noisy, which may disturb thepatient 1000, and/or that they may be disruptive to the sleep of abed-partner 1100 as a result of the passage of air through the vent.

Thus, in some forms of the present technology, the vent may beconfigured so that as the size of the aperture 3422 changes, thecross-section profile of each outer leaf surface 3418 that is exposed tothe flow of breathable gas traversing through the vent remains constant.In some configurations, the cross-section profile may remain constantirrespective of the length of the outer leaf surface 3418 that isexposed to the flow of breathable gas. Therefore, one advantage of thepresent technology may be that a cross-section profile may be chosen toreduce the noise generated by the gas washout vent arrangement, whichmay reduce disruption caused to the user and/or the bed partner of theuser. The cross-section profile design can be important for reducingnoise.

Assuming a unidirectional air flow, one suitable example design of thecross-section profile 3424 of the outer leaf surface 3418 of each of theplurality of leaves 3404 may be as shown in FIG. 16. The cross-sectionprofile of each outer leaf surface 3418 that is exposed to the flow ofbreathable gas remains constant as the size of the vent aperture 3422changes as described above. Therefore, the cross-section profile 3424may be shaped at the leading edge 3426 and the trailing edge 3428 toreduce noise generated by the flow of breathable gas as it passesthrough the aperture 3422. In such a case, the vent may be oriented foruse with the unidirectional airflow passing over the outer leaf surface3418 starting at the leading edge 3426 then proceeding across thesurface and then proceeding past the trailing edge 3428.

One suitable cross-section profile may be a ‘reverse-trumpet’ profile,similar to one disclosed in the US patent application US 2010/0051034,the entire contents of which is incorporated herein by reference.

Such a profile may include a contracting, curved leading edge 3426 thatblends into the entry side surface 3430 of each of the plurality ofleaves 3404. The profile may further include a sharply terminatingtrailing edge 3428 at the exhaust side surface 3432 as shown in FIG. 16.The leading edge 3426 may approximate a contracting curved surface andconnect to the trailing edge 3428, which may be curved and tangential toa centre axis of the aperture 3422 or converge at a small angle, such asbetween approximately 0 and approximately 15 degrees. The trailing edgemay terminate with an angle of between approximately 60 degrees andapproximately 100 degrees, such as 70 degrees, 80 degrees, or 90 degreesbetween the exit-side surface 3432 of the leaf 3404 and the trailingedge 3428.

The radius of the leading edge R2 may be between approximately 0.5 mmand approximately 1.5 mm, such as 0.75 mm, 1 mm or 1.25 mm, and theradius of the trailing edge R1 may be between approximately 1 mm andapproximately 3 mm, such as 1.5 mm, 2 mm or 2.5 mm. The thickness T1 ofeach leaf 3404 may be between approximately 1 mm and approximately 4 mm,such as 2 mm, 2.5 mm or 3 mm. The convergence in section depth C1 ofeach of the plurality of leaves 3404 may be between approximately 0.5 mmand approximately 2.5 mm, such as 1 mm, 1.5 mm or 2 mm. In otherarrangements of the present technology, where a vent arrangement isconfigured to allow air flow in either direction of the ventarrangement, a symmetric cross section profile may be preferred.

In one instance of the present technology, the vent 3400 may consist ofsix leaves 3404, wherein the thickness T1 of each leaf 3404 may be about1-4 mm, such as 2 mm, 2.5 mm or 3 mm, and the maximum distance acrosseach opposing leaves (across faces) may be about 5-15 mm, such as 6 mm,8 mm, 10 mm, 12 mm or 14 mm. In this arrangement, the vent 3400 with theaperture 3422 at the most open position would be approximately between21 mm² and 195 mm² such as 30 mm², 55 mm², 80 mm², 125 mm² or 170 mm²depending on the distance across faces and at 7 mm distance across faces(AF) the area of the aperture 3422 may be approximately 42 mm².

Another aspect of the present technology is that characteristics ofnoise generated by the flow of breathable gas through the vent 3400 maychange as the size of the vent aperture 3422 changes. One example ofsuch a noise characteristic is the level of noise generated, althoughother characteristics such as the frequency content of the noise mayalso change. An example showing changes to the measured sound powerlevel as a function of the aperture 3422 size (distance across faces)and/or the pressure is shown in FIG. 25 for one form of the presenttechnology vent 3400. For example, at approximately 10 cm H₂O ofpressure, the measured sound power level of an example of the vent 3400was approximately 30 dBA when the vent 3400 was configured with adistance across faces of approximately 4 mm. When the vent 3400 was inanother configuration with a distance across faces of approximately 7mm, the measured sound power level was approximately 32 dBA. To takeadvantage of the changing noise characteristic of the vent 3400, aplurality of vents 3400 and/or sensors may be implemented in someembodiments of the technology as will be shown in further detail below.

The dimensions of the vent 3400 may be varied under different designcircumstances, such as when varying the number of vents 3400 to beplaced on/in a patient interface 3000, or when varying therapyrequirements. As a result, the dimensions as described above should beunderstood to be only exemplary and a person skilled in the art would becapable of changing any number of the above dimensions of the vent 3400to suit their requirements.

Vent Arrangements (e.g., Sensor Enabled)

In another aspect of the current technology, a vent arrangementcomprising vents 3400 such as those described above, and/or otheradjustable (active) and non-adjustable vents, may be used to ameliorateproblems known in the art described above. Such problems to beameliorated may include potential sources of discomfort and/ordisruption caused to the patient 1000 and/or the bed-partner 1100. Thepotential sources of discomfort and/or disruption may include noisegenerated by the flow of breathable gas, whether as it passes through avent arrangement or after it passes through a vent arrangement, andjetting of flow of air onto the patient 1000 and/or onto the bed-partner1100. In one form, one or more signals indicative of potentialdisruption may be communicated from one or more sensors to a controller,such as any of the controllers described in this specification, whichmay be used to adjust the vent arrangement accordingly.

In one form, a gas washout vent arrangement may include multipleinstances of the vents 3400 (e.g., a set of vents 3400) described aboveto be placed in fluid communication with a patient interface 3000 suchas one or more of: in the plenum chamber 3200, or in a decouplingstructure 3500, or in the air circuit 4170, or in between the patientinterface 3000 and the air circuit 4170. Properties of the set of thevents 3400 may then be controlled together or separately (e.g., one,more or all of the set) to control various properties of the flow ofbreathable gas communicating through the patient interface 3000, such asnoise generated by the flow or a direction of the flow. An example ofadjusting the apertures 3422 may be by selectively moving the movableportions of the vent arrangement, which may then change flow impedancesof the multiple vents 3400 (e.g., one or more of the set).

In some instances, such a vent arrangement may be used to adjust thenoise generated from the flow of breathable gas through each vent 3400or vary the amount of flow through the vent 3400 during different phasesof the respiratory cycle. For example, the vents may be configured toopen only during the expiration phase of the respiratory cycle.

In one form of the present technology, two vents 3400 may be placed oneither side of the patient interface 3000 as shown in FIG. 22. In thisexample the two vents 3400 are positioned approximately symmetricalabout the sagittal plane once the patient 1000 puts on the patientinterface 3000. However, the vents may be located in other positions onthe patient interface 3000 as discussed further below.

One control method of achieving noise reduction may be to vary the sizeand/or orientation of the aperture 3422 of a vent arrangement (e.g. eachvent 3400) according to one or more predetermined control parameter(s).One example of such a control parameter may be measured noise levelsfrom microphones 3440 placed near each vent 3400. In another example ofa suitable control parameter may be an output from an accelerometer3442, which may be processed to indicate an orientation of the patient1000 or the patient interface. Other suitable control parameters mayinclude, pressure, flow, temperature, respiratory phase, such as whetherthe patient is in inspiration or in expiration, or therapy-relatedparameters, such as the patient's SpO2 level or whether the patientsuffers from CSR.

An exemplary set of locations of microphones 3440 or proximity sensors3444 placed near each vent 3400 or an accelerometer(s) 3442 is shown inFIG. 22, however it is to be understood that the numbers and locationsof the vents 3400, the microphones 3440, or accelerometer(s) 3442 may bevaried. Any number of other sensors known in the art, such as pressure,temperature or flow sensors may be used to provide one or more controlparameters. For example, one or more sensors to detect orientation ofthe patient interface may be implemented and the opening or closing ofone or more of the vents may be selected/controlled depending on thedetected orientation of the patient interface. In some such cases, thecontroller may open or increase the aperture of a vent(s) on a upwardlyoriented side of the mask and close or decrease the aperture of a venton a downwardly oriented side of the mask or vice versa. Thus, the ventson opposing sides of the patient interface/mask may be controlleddifferently and/or may implement dynamic selection of the direction ofventing of the mask so as to re-direct exhaust flow in differentdirections relative to the patient interface.

FIG. 26a-26b shows another form of the current technology, including avent 3400 comprising a plurality of holes and a movable portion 3456which is movable relative to the vent 3400 allowing a plurality ofconfigurations for the gas washout vent arrangement. In this form, themovable portion 3456 may be moved to adjust properties of the vent 3400.For instance, the plurality of holes in the vent 3400 may be configuredso that the flow impedance of the vent 3400 may vary depending on theposition of the movable portion 3456 (e.g. it may slide to cover/blockmore or fewer of the plurality of holes). Such movement or sliding maybe implemented through manual adjustment of movable portion or inresponse to movement and/or orientation of the patient interface itself.

For example, the vent 3400 may be configured so that the direction ofthe flow of air therethrough may differ depending on the position of themovable portion 3456 as shown in FIG. 26a-26b . For example, where theremovable portion 3456 of a vent 3400 is in a configuration as shown inFIG. 26a , the flow of exhaust gas may be generally directed towards theleft side of the mask, whereas in FIG. 26b the flow of exhaust gas maybe generally directed towards the right side of the mask. In thisregard, the dotted lines in FIG. 26a-28b and FIG. 30a-30b illustrate achange in direction (re-direction) of the flow of exhaust gas as it isexhausted from the patient interface responsive to the re-positioning ofthe movable portion.

Alternatively, or additionally, some of the holes of the vent may beconfigured for inward flow only and some of the hole of the vent may beconfigured for outward flow only such as with a one way valves. Thus,when the slide is moved vent may selectively permit inward flow and/oroutward flow.

Such a vent 3400 may then be configured be adjusted based on one or morecontrol parameters, such as outputs from one or more sensors such as amicrophone 3440 or an accelerometer 3442 and/or in some cases thevent(s) may be adjusted by the gravitational orientation of the mask.

For instance, the movable portion 3456 in such a vent 3400 shown in FIG.26a and FIG. 26b may be configured to slide according to an orientationof the patient. This may be implemented by the use of an accelerometeras described above and a suitable actuator, or by configuring themovable portion 3456 to slide due to gravity (e.g., weighted movement ofthe sliding moveable portion) following orientation of the vent 3400.FIG. 29 shows an instance where the patient 1000 is lying in a bed withher head tilted towards her left. Accordingly, the movable portion 3456becomes oriented towards the left side of the patient 1000, changing thedirection of the flow of exhaust air away to be away from the bed. Insome cases, the movable portion may include additional weights toovercome static friction and/or airflow in order for the movable portion3456 to slide relative to the vent 3400. FIG. 27a and FIG. 27b showanother type of a patient interface 3000 (nasal mask) which incorporatesa vent 3400 including a movable portion 3456.

In another form, the vent 3400 may be configured as shown in FIG. 28aand FIG. 28b . The vent 3400 in FIG. 28a includes one or more of amovable portion 3456 in the form of a prism or ball, and configured tomove along or within one or more of a guiding portion 3458 such as anopen ended channel CC. Optionally, each of the open ends (OE1, OE2) maycomprise a plurality of holes to vent air from the plenum chamber and aportion of the channel CC (e.g., an inside portion) may be in aircommunication with the air of the plenum chamber. Thus, the guidingportion 3458 may comprise a plurality of apertures, such as at a firstend of the guiding portion and a second end of guiding portion, which(or portions thereof) may be opened and/or closed according to amovement of the movable portion 3456. For example, by re-positioning theorientation of the patient interface such that the guiding portion orchannel will have a lower end and a higher end. As a result, gravity mayre-position the weighted prism or ball to the lower end (e.g., bysliding or rolling in and along the channel) of the guiding portion orchannel so that the prism or ball will move to seal or partially sealthe lower end of the guide portion or channel and thereby open orincrease the opening of the higher end for exhaust venting. In this wayand similar to other movable portion embodiments described herein, theflow of the exhaust venting may be periodically re-directed from oneside of the patient interface to the other, enforcing an upward (e.g.,away from mattress) venting direction even as the mask is re-positionedfrom one side to another as the patient, wearing the patient interface,rolls in bed. In some cases, repositioning may cause the movable portionto be more centrally located between the ends of the guiding portion(e.g., when a patient with the patient interface is lying on his/herback). As such, venting flow at both open ends depending on the ventcharacteristics may be reduced since the moveable portion is blockingneither end. This dual end open situation may reduce vent flow at bothends including the end in a direction of a bed partner when compared toa situation when only one end is blocked and one end is open. Of course,such venting schemes may also be enforced with one or more orientationsensors and electro-mechanical control of different vents (such as anyof the vents disclosed in this specification) on opposing sides of thepatient interface or one or more of such vents configured to changeexhaust flow direction.

In a yet another form, the vent 3400 may include a movable portion 3456,as shown in FIG. 30a and FIG. 30b , where the movable portion 3456includes one or more holes for washout of exhaust gas. In thearrangement shown in FIG. 30a and FIG. 30b , the movable portion 3456includes an aperture 3457 to allow fluid communication between theinside of the plenum chamber 3200 and the ambient environment. Themoveable portion forms a swivel that can pivot, such as by mechanicalactuator (such as a stepper motor with a gear coupled with a side of theswivel to rotate the swivel) and/or gravitation rotation (e.g., weightedon one side of the swivel or counter balanced). In this regard, a flowchannel FC of the swivel with an inside opening CIO to the plenumchamber can rotate with the swivel to change the direction from whichflow exits the aperture of the swivel. Thus, when the patient interfaceis re-oriented such as from side to side, flow can be re-directed, suchas to enforce an upward flow (e.g., away from mattress) or away from thepatient's bed partner. Accordingly, the movable portion 3456 may move inresponse to one or more control parameters, such as outputs from one ormore sensors such as a microphone 3440 or an accelerometer 3442 or dueto patient orientation resulting in adjustment or movement of theaperture 3457.

Of course, any vent configured with one or more adjustable properties ofthe vent, such as a direction of air flow therethrough or the pneumaticimpedance, may be used in conjunction with one or more sensors and/orthe control methodologies as described above. For example, any number ofvents disclosed in PCT patent application number PCT/US2012/055148 maybe implemented with the above aspect(s) of the present technology.

According to another aspect of the present technology, the one or moresignals indicative of potential disruption (e.g., vent related noise)may be correlated with an indicator of disruption to the patient 1000and/or the bed-partner 1100. In one form, an indicator of arousal suchas those known in the art (e.g., one detected by processor analysis of aflow signal and/or a signal from a movement sensor) may be correlatedwith the indicator of disruption. In such a case, the controller may beconfigured to control adjustments to the vent arrangement based on thearousal indicator and the disruption indicator. For example, theprocessor may control changes to the vent when arousal is indicated andthe signal(s) indicative of potential disruption such as noise is abovea threshold. One example of prior art documenting detecting indicatorsof arousal in the prior art may be in the PCT patent application WO2011/006199, the contents of which are incorporated herein bycross-reference. Detection of arousal then may be combined with any ofthe above indicators of potential disruption in order to betterdetermine whether the potentially disruptive indicators would warrant anadjustment to the vent arrangement.

Example Control Functions

A number of example control functions are described below. Suchmethodologies may be implemented by any of the controllers describedthroughout this specification. Although the control functions may bedrawn and/or described based on a specific number of vents 3400 and/orconfigurations of vents 3400, it should be understood that they may beadapted to suit any number of vents 3400 and/or configurations of vents3400 while still taking advantage of the present technology.

Vent Aperture Sizing Control Function A 34610

FIG. 17 shows a flow chart of one form of a vent aperture sizing controlfunction 34610 for controlling a size of the aperture 3422. The ventaperture sizing control function A 34610 may control the size of theaperture 3422 of each vent 3400 as a function of one or more controlparameters, for example such as those described above. In step 34612,the vent aperture sizing control function A 34610 may determine value(s)of the control parameter. The value(s) of the control parameter maycomprise, for example, noise levels as measured by the microphones 3440placed near each vent 3400 and/or a signal indicating the orientation ofthe patient 1000, or other inputs as described above. The vent aperturesizing control function A 34610 may determine desired opening sizes instep 34614 for apertures 3422, for instance based on the value(s) of thecontrol parameter(s). Step 34614 may be carried out using a look-uptable or a predetermined vent sizing function configured to determinedesired changes to vent sizing based on the inputs of the value(s) ofthe control parameter(s). The vent aperture sizing protocol may thencommunicate in step 34616 the desired aperture opening sizes (or othersuitable control signal) to the controller's actuator to adjust thesizes of each vent apertures 3422 accordingly.

Vent Aperture Sizing Control Function B 34620

Another form of a vent aperture sizing function is shown as a flowchartin FIG. 18. The vent aperture sizing control function B 34620 isdescribed based on two vents 3400 in a vent arrangement (e.g. as shownin FIG. 22). In this form, the vent aperture sizing control function B34620 may open both vents 3400 in step 34622 to ensure equal operatingconditions for the vents 3400. As a next step 34624, the controlfunction B 34620 may determine noise levels (N1 and N2), for example bymeasurement at two microphones 3440 that are placed near each vent 3400as shown in step 34623. The vent sizing function may then compare thenoise levels N1 and N2 in step 34626, and in step 34628 act to close orpartially close the vent 3400 that is creating more noise.

Vent Aperture Sizing Control Function C 34630

Another form of a vent aperture sizing function is shown as a flowchartin FIG. 19, where the vent arrangement comprises two vents 3400 (e.g. asshown in FIG. 22). In step 34632, the vent aperture sizing controlfunction C 34630 may determine noise levels N1 and N2, respectively ateach vent 3400. The control function C 34630 may determine two noiselevels (N1 and N2) in step 34631, for example by receiving data orsignals representing them from two microphones 3440 that are placed neareach vent 3400. The control function C 34630 may also receive data orsignals representing areas of apertures 3422 (S1 and S2) from each vent3400 for example from step 34638. The vent sizing function would comparethe noise levels N1 and N2 in step 34634, and step 34638 may adjust thesizes of the aperture 3422 based on a difference in noise levels N1 andN2. A threshold step 34636 may be included so that the step 34638 mayonly be activated if the difference in noise levels N1 and N2 exceed adifference threshold ΔN_(threshold).

In one form of the step 34638, the control function C 34630 may act toreduce the size of the aperture 3422 of the corresponding vent 3400where the noise level was found to be higher, and/or increase the sizeof the aperture 3422 of the corresponding vent 3400 where the noiselevel was found to be lower. Furthermore, the size of the aperture 3422of each vent 3400 may be adjusted by a predetermined increment until thenoise levels N1 and N2 are substantially equal to each other, or untilthe difference in noise levels is under a predetermined threshold.

Yet further, in the vent sizing functions described above, the functionmay also compare the noise levels N1 and N2 against a threshold valueN_(threshold) and only adjust the size(s) of the vent aperture(s) 3422if one or both values are above and/or below N_(threshold).

Vent Aperture Sizing Control Function D 34640

Another form of a vent sizing function is shown as a flowchart in FIG.20. In this example, the vent aperture sizing control function D 34640may determine an orientation of a patient 1000 in step 34642. Forinstance, the sizing control function D may receive a signal in step34641 indicating at least one of the orientation of the patient 1000 orthe orientation of the patient interface 3000 from an accelerometer3442. The vent aperture sizing control function D 34640 may then adjustthe sizes of vent apertures 3422 in step 34644 based on the orientationdetermined in step 34642.

For instance, in operation, the step 34644 may send a signal to thevents 3400 to reduce the size of the aperture 3422 of the correspondingvent 3400 which is closer to the ground (e.g., vent oriented downward),and increase the size of the aperture 3422 of the corresponding vent3400 which is further from the ground (e.g., vent oriented upward).Adjustment of vent aperture size according to patient orientation as insizing control function D 34640 may reduce noise generated by thepatient interface 3000 from impingement of the flow of breathable gas.Such noise may be generated from impingement upon an obstruction such apillow, or bedding is known to generate additional noise in comparisonto the unobstructed flow of breathable gas exiting the vent 3400 exitsinto the atmosphere.

Furthermore, by adjustment of vent aperture size according to patientorientation as in sizing control function D 34640, it may also bepossible to reduce the amount of exiting flow of breathable gas from avent 3400 that is directed at a bed partner 1100, which may reduceannoyances and/or additional noise experienced by the bed partner. Forexample, the controller may include an input setting to indicate whichside of the bed on which a patient sleeps relative to bed partner 1100.In the event that the controller detects an orientation of the patientinterface, such as with the orientation sensor(s)/accelerometer(s), thatindicates that the patient 1000 is sleeping on his/her back, thecontroller may then, based on the setting, reduce the flow of venting onthe side of the bed partner. For example, the controller may then selectto open or open more a vent of the patient interface opposite the bedpartner and/or close or open less a vent of the patient interfaceadjacent to the bed partner.

In another form of the present technology (not shown), the vent aperturesizing control function may receive a signal from a proximity sensor3444 indicating the proximity of the patient 1000 to its bed partner1100 or another obstruction to each vent 3400 in the direction of itsaperture 3422. The vent sizing function may then act to adjust sizes ofthe vent apertures 3422 accordingly, such as reduce the size of theaperture 3422 of the corresponding vent 3400 which is closer to the bedpartner 1100 or obstruction, and increase the size of the aperture 3422of the corresponding vent 3400 which is further from the bed partner1100 or obstruction. It is to be understood that the vent sizingfunction may also receive and react to a signal from other types ofsensors, such as from a modulated pulse Doppler based sensor such as onedisclosed in U.S. Pat. No. 6,426,716 or a sensor described in US patentapplication number 2009/0203972, the entire contents of which areincluded herein by reference. Such a sensor may serve as a proximitysensor and/or orientation sensor in some versions of the presenttechnology.

In a yet another example of the current technology, the vent aperturesizing control function may receive and react to a signal indicatingwhether the patient 1000 is in an inspiration phase or in expirationphase of the breathing cycle. According to this signal the vent sizingfunction may, for example, close the vent 3400 during the inspirationphase of the patient's breath, and open the vent 3400 during theexpiration phase of the patient's breath.

Although a number of above paragraphs discuss means of determining sizesof apertures 3422 of vents 3400 using a vent aperture sizing control‘function’, it should be understood that use of the term ‘function’ doesnot preclude use of a multi-dimensional look-up table by themselves orin conjunction with a mathematical function.

Vent Aperture Sizing Control Function E 34650

Another instance of the current technology that utilises a look-up tableis shown in FIG. 21. This vent aperture sizing control function E 34650may determine noise levels N1 and N2 near each vent 3400 in step 34652,possibly using measurements from sensors such as microphones in step34651. A differential noise value Nd, may be calculated in step 34653 asa difference between the two noise levels N1 and N2, which may becompared against a threshold N_(threshold) in step 34654. An amount bywhich to adjust the size of the aperture 3422 (ΔΔrea) may be determined(for example from a look-up table) as shown in step 34655, and the ventaperture sizes may be adjusted based on this value in step 34656. Theadjusted, resulting sizes of vent apertures 3422 may also be passed onto step 34652 as an input from step 34656.

It is to be understood that the control protocols and means describedabove are not to be limited only to the instance of the current vent3400 and vent arrangement technology. A comparable performance toadjusting sizes of vent apertures 3422 of multiple vents 3400 accordingto sensor inputs may be also performed by a single vent assembly thatallows the flow of breathable air to be re-directed. For instance, asingle vent assembly that has an actuator for movement of its aperturealong the sagittal plane may allow the vent to direct its outflow to theleft or the right side of the patient 1000 according to a sensor inputas described above and/or according to any of the adjustment controlmethodologies described herein.

Decoupling Structure(s)

In one form the patient interface 3000 includes at least one decouplingstructure, for example a swivel 3510 (see FIG. 29) or a ball and socket3520 (see FIG. 27a ).

Connection Port 3600

Connection port 3600 allows for connection to the air circuit 4170.

Forehead Support 3700

In one form, the patient interface 3000 includes a forehead support3700.

Anti-Asphyxia Valve

In one form, the patient interface 3000 includes an anti-asphyxia valve.

Ports

In one form of the present technology, a patient interface 3000 includesone or more ports that allow access to the volume within the plenumchamber 3200. In one form this allows a clinician to supply supplementaloxygen. In one form this allows for the direct measurement of a propertyof gases within the plenum chamber 3200, such as the pressure.

RPT Device 4000

An example RPT device 4000 that may be suitable for implementing aspectsof the present technology may include mechanical and pneumaticcomponents 4100, electrical components 4200 and may be programmed toexecute one or more of the control methodologies or algorithms describedthroughout this specification. The RPT device may have an externalhousing 4010, preferably formed in two parts, an upper portion 4012 ofthe external housing 4010, and a lower portion 4014 of the externalhousing 4010. In alternative forms, the external housing 4010 mayinclude one or more panel(s) 4015. Preferably the RPT device 4000comprises a chassis 4016 that supports one or more internal componentsof the RPT device 4000. In one form a pneumatic block 4020 is supportedby, or formed as part of the chassis 4016. The RPT device 4000 mayinclude a handle 4018.

The pneumatic path of the RPT device 4000 preferably comprises an inletair filter 4112, an inlet muffler 4122, a controllable pressure device4140 capable of supplying air at positive pressure (preferably a blower4142), and an outlet muffler 4124. One or more pressure sensors 4272 andflow sensors 4274 are included in the pneumatic path.

The preferred pneumatic block 4020 comprises a portion of the pneumaticpath that is located within the external housing 4010.

The RPT device 4000 preferably has an electrical power supply 4210, oneor more input devices 4220, a central controller 4230, a therapy devicecontroller 4240 and/or any of the controllers previously described, apressure device 4140, one or more protection circuits 4250, memory 4260,transducers 4270, data communication interface 4280 and one or moreoutput devices 4290. Electrical components 4200 may be mounted on asingle Printed Circuit Board Assembly (PCBA) 4202. In an alternativeform, the RPT device 4000 may include more than one PCBA 4202.

The central controller 4230 of the RPT device 4000, which may includeone or more processors, can be programmed to execute one or morealgorithm modules, preferably including a pre-processing module, atherapy engine module, a pressure control module, and further preferablya fault condition module. It may further include a vent control modulethat may be configured with one or more of the vent controlmethodologies described throughout this specification.

RPT Device Mechanical & Pneumatic Components 4100

Air Filter(s) 4110

A RPT device in accordance with one form of the present technology mayinclude an air filter 4110, or a plurality of air filters 4110.

In one form, an inlet air filter 4112 is located at the beginning of thepneumatic path upstream of a blower 4142. See FIG. 4 b.

In one form, an outlet air filter 4114, for example an antibacterialfilter, is located between an outlet of the pneumatic block 4020 and apatient interface 3000. See FIG. 4 b.

Muffler(s) 4120

In one form of the present technology, an inlet muffler 4122 is locatedin the pneumatic path upstream of a blower 4142. See FIG. 4 b.

In one form of the present technology, an outlet muffler 4124 is locatedin the pneumatic path between the blower 4142 and a patient interface3000. See FIG. 4 b.

Pressure Device 4140

In a preferred form of the present technology, a pressure device 4140for producing a flow of air at positive pressure is a controllableblower 4142. For example the blower may include a brushless DC motor4144 with one or more impellers housed in a volute. The blower may bepreferably capable of delivering a supply of air, for example about 120litres/minute, at a positive pressure in a range from about 4 cmH₂O toabout 20 cmH₂O, or in other forms up to about 30 cmH₂O.

The pressure device 4140 is under the control of the therapy devicecontroller 4240.

Transducer(s) 4270

In one form of the present technology, one or more transducers 4270 arelocated upstream of the pressure device 4140. The one or moretransducers 4270 are constructed and arranged to measure properties ofthe air at that point in the pneumatic path.

In one form of the present technology, one or more transducers 4270 arelocated downstream of the pressure device 4140, and upstream of the aircircuit 4170. The one or more transducers 4270 are constructed andarranged to measure properties of the air at that point in the pneumaticpath.

In one form of the present technology, one or more transducers 4270 arelocated proximate to the patient interface 3000.

Anti-Spill Back Valve 4160

In one form of the present technology, an anti-spill back valve islocated between the humidifier 5000 and the pneumatic block 4020. Theanti-spill back valve is constructed and arranged to reduce the riskthat water will flow upstream from the humidifier 5000, for example tothe motor 4144.

Air Circuit 4170

An air circuit 4170 in accordance with an aspect of the presenttechnology is constructed and arranged to allow a flow of air orbreathable gasses between the pneumatic block 4020 and the patientinterface 3000.

Oxygen Delivery

In one form of the present technology, supplemental oxygen 4180 isdelivered to a point in the pneumatic path.

In one form of the present technology, supplemental oxygen 4180 isdelivered upstream of the pneumatic block 4020.

In one form of the present technology, supplemental oxygen 4180 isdelivered to the air circuit 4170.

In one form of the present technology, supplemental oxygen 4180 isdelivered to the patient interface 3000.

RPT Device Electrical Components 4200

Power Supply 4210

In one form of the present technology power supply 4210 is internal ofthe external housing 4010 of the RPT device 4000. In another form of thepresent technology, power supply 4210 is external of the externalhousing 4010 of the RPT device 4000.

In one form of the present technology power supply 4210 provideselectrical power to the RPT device 4000 only. In another form of thepresent technology, power supply 4210 provides electrical power to bothRPT device 4000 and humidifier 5000. The power supply may alsooptionally provide power to any actuator, controller and/or sensors fora vent arrangement as described throughout this specification

Input Devices 4220

In one form of the present technology, a RPT device 4000 includes one ormore input devices 4220 in the form of buttons, switches or dials toallow a person to interact with the device. These may be implemented forentering settings for operation of the components of the RPT device suchas the vent arrangement. The buttons, switches or dials may be physicaldevices, or software devices accessible via a touch screen. The buttons,switches or dials may, in one form, be physically connected to theexternal housing 4010, or may, in another form, be in wirelesscommunication with a receiver that is in electrical connection to thecentral controller 4230.

In one form the input device 4220 may be constructed and arranged toallow a person to select a value and/or a menu option.

Central Controller 4230

In one form of the present technology, the central controller 4230 is adedicated electronic circuit configured to receive input signal(s) fromthe input device 4220, and to provide output signal(s) to the outputdevice 4290 and/or the therapy device controller 4240.

In one form, the central controller 4230 is an application-specificintegrated circuit. In another form, the central controller 4230comprises discrete electronic components.

In another form of the present technology, the central controller 4230is a processor suitable to control a RPT device 4000 such as an x86INTEL processor.

A processor of a central controller 4230 suitable to control a RPTdevice 4000 in accordance with another form of the present technologyincludes a processor based on ARM Cortex-M processor from ARM Holdings.For example, an STM32 series microcontroller from ST MICROELECTRONICSmay be used.

Another processor suitable to control a RPT device 4000 in accordancewith a further alternative form of the present technology includes amember selected from the family ARM9-based 32-bit RISC CPUs. Forexample, an STR9 series microcontroller from ST MICROELECTRONICS may beused.

In certain alternative forms of the present technology, a 16-bit RISCCPU may be used as the processor for the RPT device 4000. For example aprocessor from the MSP430 family of microcontrollers, manufactured byTEXAS INSTRUMENTS, may be used.

The processor is configured to receive input signal(s) from one or moretransducers 4270, and one or more input devices 4220.

The processor is configured to provide output signal(s) to one or moreof an output device 4290, a therapy device controller 4240, a datacommunication interface 4280 and humidifier controller 5250.

In some forms of the present technology, the processor of the centralcontroller 4230, or multiple such processors, is configured to implementthe one or more methodologies described herein such as the one or morealgorithms 4300 expressed as computer programs stored in anon-transitory computer readable storage medium, such as memory 4260. Insome cases, as previously discussed, such processor(s) may be integratedwith a RPT device 4000. However, in some forms of the present technologythe processor(s) may be implemented discretely from the flow generationcomponents of the RPT device 4000, such as for purpose of performing anyof the methodologies described herein without directly controllingdelivery of a respiratory treatment. For example, such a processor mayperform any of the methodologies described herein for purposes ofdetermining control settings for a ventilator or other respiratoryrelated events by analysis of stored data such as from any of thesensors described herein. Similarly, such a processor may perform any ofthe methodologies described herein for purposes controlling operation ofany vent arrangement described in this specification.

Clock 4232

Preferably RPT device 4000 includes a clock 4232 that is connected toprocessor.

Therapy Device Controller 4240

In one form of the present technology, therapy device controller 4240 isa pressure control module 4330 that forms part of the algorithms 4300executed by the processor of the central controller 4230.

In one form of the present technology, therapy device controller 4240 isa dedicated motor control integrated circuit. For example, in one form aMC33035 brushless DC motor controller, manufactured by ONSEMI is used.

Protection Circuits 4250

Preferably a RPT device 4000 in accordance with the present technologycomprises one or more protection circuits 4250.

One form of protection circuit 4250 in accordance with the presenttechnology is an electrical protection circuit.

One form of protection circuit 4250 in accordance with the presenttechnology is a temperature or pressure safety circuit.

Memory 4260

In accordance with one form of the present technology the RPT device4000 includes memory 4260, preferably non-volatile memory. In someforms, memory 4260 may include battery powered static RAM. In someforms, memory 4260 may include volatile RAM.

Preferably memory 4260 is located on PCBA 4202. Memory 4260 may be inthe form of EEPROM, or NAND flash.

Additionally or alternatively, RPT device 4000 includes removable formof memory 4260, for example a memory card made in accordance with theSecure Digital (SD) standard.

In one form of the present technology, the memory 4260 acts as anon-transitory computer readable storage medium on which is storedcomputer program instructions expressing the one or more methodologiesdescribed herein, such as the one or more algorithms 4300.

Transducers 4270

Transducers may be internal of the device, or external of the RPTdevice. External transducers may be located for example on or form partof the air delivery circuit, e.g. the patient interface. Externaltransducers may be in the form of non-contact sensors such as a Dopplerradar movement sensor that transmit or transfer data to the RPT device.

Flow

A flow transducer 4274 in accordance with the present technology may bebased on a differential pressure transducer, for example, an SDP600Series differential pressure transducer from SENSIRION. The differentialpressure transducer is in fluid communication with the pneumaticcircuit, with one of each of the pressure transducers connected torespective first and second points in a flow restricting element.

In use, a signal representing total flow Qt from the flow transducer4274 is received by the processor.

Pressure

A pressure transducer 4272 in accordance with the present technology islocated in fluid communication with the pneumatic circuit. An example ofa suitable pressure transducer is a sensor from the HONEYWELL ASDXseries. An alternative suitable pressure transducer is a sensor from theNPA Series from GENERAL ELECTRIC.

In use, a signal from the pressure transducer 4272, is received by thecentral controller processor. In one form, the signal from the pressuretransducer 4272 is filtered prior to being received by the centralcontroller 4230.

Motor Speed

In one form of the present technology a motor speed signal 4276 isgenerated. A motor speed signal 4276 is preferably provided by therapydevice controller 4240. Motor speed may, for example, be generated by aspeed sensor, such as a Hall effect sensor.

Data Communication Systems 4280

In one preferred form of the present technology, a data communicationinterface 4280 is provided, and is connected to central controllerprocessor. Data communication interface 4280 is preferably connectableto remote external communication network 4282. Data communicationinterface 4280 is preferably connectable to local external communicationnetwork 4284. Preferably remote external communication network 4282 isconnectable to remote external device 4286. Preferably local externalcommunication network 4284 is connectable to local external device 4288.

In one form, data communication interface 4280 is part of processor ofcentral controller 4230. In another form, data communication interface4280 is an integrated circuit that is separate from the centralcontroller processor.

In one form, remote external communication network 4282 is the Internet.The data communication interface 4280 may use wired communication (e.g.via Ethernet, or optical fibre) or a wireless protocol to connect to theInternet.

In one form, local external communication network 4284 utilises one ormore communication standards, such as Bluetooth, or a consumer infraredprotocol.

In one form, remote external device 4286 is one or more computers, forexample a cluster of networked computers. In one form, remote externaldevice 4286 may be virtual computers, rather than physical computers. Ineither case, such remote external device 4286 may be accessible to anappropriately authorised person such as a clinician.

Preferably local external device 4288 is a personal computer, mobilephone, tablet or remote control.

Output Devices Including Optional Display, Alarms

An output device 4290 in accordance with the present technology may takethe form of one or more of a visual, audio and haptic unit. A visualdisplay may be a Liquid Crystal Display (LCD) or Light Emitting Diode(LED) display.

Display Driver 4292

A display driver 4292 receives as an input the characters, symbols, orimages intended for display on the display 4294, and converts them tocommands that cause the display 4294 to display those characters,symbols, or images.

Display 4294

A display 4294 is configured to visually display characters, symbols, orimages in response to commands received from the display driver 4292.For example, the display 4294 may be an eight-segment display, in whichcase the display driver 4292 converts each character or symbol, such asthe figure “0”, to eight logical signals indicating whether the eightrespective segments are to be activated to display a particularcharacter or symbol.

GLOSSARY

In certain forms of the present technology, one or more of the followingdefinitions may apply. In other forms of the present technology,alternative definitions may apply.

General

Air: Air will be taken to include breathable gases, for example air withsupplemental oxygen.

Continuous Positive Airway Pressure (CPAP): CPAP treatment will be takento mean the application of a supply of air or breathable gas to theentrance to the airways at a pressure that is continuously positive withrespect to atmosphere, and preferably approximately constant through arespiratory cycle of a patient. In some forms, the pressure at theentrance to the airways will vary by a few centimeters of water within asingle respiratory cycle, for example being higher during inhalation andlower during exhalation. In some forms, the pressure at the entrance tothe airways will be slightly higher during exhalation, and slightlylower during inhalation. In some forms, the pressure will vary betweendifferent respiratory cycles of the patient, for example being increasedin response to detection of indications of partial upper airwayobstruction, and decreased in the absence of indications of partialupper airway obstruction.

Materials

Silicone or Silicone Elastomer: A synthetic rubber. In thisspecification, a reference to silicone is a reference to liquid siliconerubber (LSR) or a compression moulded silicone rubber (CMSR). One formof commercially available LSR is SILASTIC (included in the range ofproducts sold under this trademark), manufactured by Dow Corning.Another manufacturer of LSR is Wacker. Unless otherwise specified to thecontrary, a preferred form of LSR has a Shore A (or Type A) indentationhardness in the range of about 35 to about 45 as measured using ASTMD2240.

Polycarbonate: a typically transparent thermoplastic polymer ofBisphenol-A Carbonate.

Aspects of a Patient Interface

Anti-asphyxia valve (AAV): The component or sub-assembly of a masksystem that, by opening to atmosphere in a failsafe manner, reduces therisk of excessive CO₂ rebreathing by a patient.

Elbow: A conduit that directs an axis of flow of air to change directionthrough an angle. In one form, the angle may be approximately 90degrees. In another form, the angle may be less than 90 degrees. Theconduit may have an approximately circular cross-section. In anotherform the conduit may have an oval or rectangular cross-section.

Frame: Frame will be taken to mean a mask structure that bears the loadof tension between two or more points of connection with a headgear. Amask frame may be a non-airtight load bearing structure in the mask.However, some forms of mask frame may also be air-tight.

Headgear: Headgear will be taken to mean a form of positioning andstabilizing structure designed for use on a head. Preferably theheadgear comprises a collection of one or more struts, ties andstiffeners configured to locate and retain a patient interface inposition on a patient's face for delivery of respiratory therapy. Someties are formed of a soft, flexible, elastic material such as alaminated composite of foam and fabric.

Membrane: Membrane will be taken to mean a typically thin element thathas, preferably, substantially no resistance to bending, but hasresistance to being stretched.

Plenum chamber: a patient interface plenum chamber will be taken to meana portion of a patient interface having walls enclosing a volume ofspace, such as for a full-face mask (e.g., nose and mouth mask), a nasalmask or a nasal pillow, the volume having air therein pressurised aboveatmospheric pressure in use by the patient. A shell may form part of thewalls of a patient interface plenum chamber. In one form, a region ofthe patient's face abuts one of the walls of the plenum chamber, such asvia a cushion or seal.

Seal: The noun form (“a seal”) will be taken to mean a structure orbarrier that intentionally resists the flow of air through the interfaceof two surfaces. The verb form (“to seal”) will be taken to mean toresist a flow of air.

Shell: A shell will preferably be taken to mean a curved structurehaving bending, tensile and compressive stiffness, for example, aportion of a mask that forms a curved structural wall of the mask.Preferably, compared to its overall dimensions it is relatively thin. Insome forms, a shell may be faceted. Preferably such walls are airtight,although in some forms they may not be airtight.

Stiffener: A stiffener will be taken to mean a structural componentdesigned to increase the bending resistance of another component in atleast one direction.

Strut: A strut will be taken to be a structural component designed toincrease the compression resistance of another component in at least onedirection.

Swivel: (noun) A subassembly of components configured to rotate about acommon axis, preferably independently, preferably under low torque. Inone form, the swivel may be constructed to rotate through an angle of atleast 360 degrees. In another form, the swivel may be constructed torotate through an angle less than 360 degrees. When used in the contextof an air delivery conduit, the sub-assembly of components preferablycomprises a matched pair of cylindrical conduits. Preferably there islittle or no leak flow of air from the swivel in use.

Tie: A tie will be taken to be a structural component designed to resisttension.

Vent: (noun) the structure that allows a deliberate controlled rate leakof air from an interior of the mask, or conduit to ambient air, to allowwashout of exhaled carbon dioxide (CO₂) and supply of oxygen (O₂).

Other Remarks

A portion of the disclosure of this patent document contains materialwhich is subject to copyright protection. The copyright owner has noobjection to the facsimile reproduction by anyone of the patent documentor the patent disclosure, as it appears in the Patent and TrademarkOffice patent file or records, but otherwise reserves all copyrightrights whatsoever.

Unless the context clearly dictates otherwise and where a range ofvalues is provided, it is understood that each intervening value, to thetenth of the unit of the lower limit, between the upper and lower limitof that range, and any other stated or intervening value in that statedrange is encompassed within the technology. The upper and lower limitsof these intervening ranges, which may be independently included in theintervening ranges, are also encompassed within the technology, subjectto any specifically excluded limit in the stated range. Where the statedrange includes one or both of the limits, ranges excluding either orboth of those included limits are also included in the technology.

Furthermore, where a value or values are stated herein as beingimplemented as part of the technology, it is understood that such valuesmay be approximated, unless otherwise stated, and such values may beutilized to any suitable significant digit to the extent that apractical technical implementation may permit or require it.

Unless defined otherwise, all technical and scientific terms used hereinhave the same meaning as commonly understood by one of ordinary skill inthe art to which this technology belongs. Although any methods andmaterials similar or equivalent to those described herein can also beused in the practice or testing of the present technology, a limitednumber of the exemplary methods and materials are described herein.

When a particular material is identified as being preferably used toconstruct a component, obvious alternative materials with similarproperties may be used as a substitute. Furthermore, unless specified tothe contrary, any and all components herein described are understood tobe capable of being manufactured and, as such, may be manufacturedtogether or separately.

It must be noted that as used herein and in the appended claims, thesingular forms “a”, “an”, and “the” include their plural equivalents,unless the context clearly dictates otherwise.

All publications mentioned herein are incorporated by reference todisclose and describe the methods and/or materials which are the subjectof those publications. The publications discussed herein are providedsolely for their disclosure prior to the filing date of the presentapplication. Nothing herein is to be construed as an admission that thepresent technology is not entitled to antedate such publication byvirtue of prior invention. Further, the dates of publication providedmay be different from the actual publication dates, which may need to beindependently confirmed.

Moreover, in interpreting the disclosure, all terms should beinterpreted in the broadest reasonable manner consistent with thecontext. In particular, the terms “comprises” and “comprising” should beinterpreted as referring to elements, components, or steps in anon-exclusive manner, indicating that the referenced elements,components, or steps may be present, or utilized, or combined with otherelements, components, or steps that are not expressly referenced.

The subject headings used in the detailed description are included onlyfor the ease of reference of the reader and should not be used to limitthe subject matter found throughout the disclosure or the claims. Thesubject headings should not be used in construing the scope of theclaims or the claim limitations.

Although the technology herein has been described with reference toparticular embodiments, it is to be understood that these embodimentsare merely illustrative of the principles and applications of thetechnology. In some instances, the terminology and symbols may implyspecific details that are not required to practice the technology. Forexample, although the terms “first” and “second” may be used, unlessotherwise specified, they are not intended to indicate any order but maybe utilised to distinguish between distinct elements. Furthermore,although process steps in the methodologies may be described orillustrated in an order, such an ordering is not required. Those skilledin the art will recognize that such ordering may be modified and/oraspects thereof may be conducted concurrently or even synchronously.

It is therefore to be understood that numerous modifications may be madeto the illustrative embodiments and that other arrangements may bedevised without departing from the spirit and scope of the technology.

REFERENCE SIGNS LIST

-   1000 patient-   1100 bed-partner-   3000 patient interface-   3100 seal-forming structure-   3200 plenum chamber-   3210 perimeter-   3300 structure-   3400 vent-   3404 leaf-   3406 guide ring-   3408 outer housing-   3410 guide ring key-   3412 guide slot-   3414 leaf key-   3416 outer housing guide slot-   3418 outer leaf surface-   3420 inner leaf surface-   3422 aperture-   3424 section profile-   3426 leading edge-   3428 trailing edge-   3430 entry side surface-   3432 side surface-   3440 microphone-   3442 accelerometer-   3444 proximity sensor-   3452 magnet ring-   3454 coil-   3456 movable portion-   3457 aperture-   3458 guiding portion-   34610 vent aperture sizing control function A-   34612 sizing control function A—step 1-   34614 sizing control function A—step 5-   34616 sizing control function A—step 3-   34620 vent aperture sizing control function B-   34622 sizing control function B—step 1-   34623 sizing control function B—step 2 a-   34624 sizing control function B—step 2-   34626 sizing control function B—step 3-   34628 sizing control function B—step 4-   34630 vent aperture sizing control function C-   34631 sizing control function C—step 1 a-   34632 sizing control function C—step 1-   34634 sizing control function C—step 2-   34636 sizing control function C—step 3-   34638 sizing control function C—step 4-   34640 vent aperture sizing control function D-   34641 sizing control function D—step 1 a-   34642 sizing control function D—step 1-   34644 sizing control function D—step 2-   34650 vent aperture sizing control function E-   34651 sizing control function C—step 1 a-   34652 sizing control function C—step 1-   34653 sizing control function C—step 2-   34654 sizing control function C—step 3-   34655 sizing control function C—step 4-   34656 sizing control function C—step 4-   34710 first calibration cycle-   34712 first calibration cycle—step 1-   34714 first calibration cycle—step 2-   34716 first calibration cycle—step 3-   34717 first calibration cycle—step 4-   34718 first calibration cycle—step 5-   34720 second calibration cycle-   34722 second calibration cycle—step 1-   34724 second calibration cycle—step 2-   34726 second calibration cycle—step 3-   34727 second calibration cycle—step 4-   34728 second calibration cycle—step 5-   3480 actuator-   3510 swivel-   3520 ball and socket-   3600 connection port-   3700 forehead support-   4170 air circuit-   4322 adjustable vent aperture

The invention claimed is:
 1. A system comprising a respiratory mask fordelivering a supply of breathable gas to the entrance of a patient'sairways for amelioration or treatment of a respiratory disorder, therespiratory mask having venting apparatus configured to vent a plenumchamber of the respiratory mask to ambient, the venting apparatuscomprising: a first adjustable vent; a second adjustable vent; andactuator apparatus on the mask to (1) automatically vary the firstadjustable vent in response to a first control system signal foradjusting the first adjustable vent, and (2) to automatically vary thesecond adjustable vent in response to a second control system signal foradjusting the second adjustable vent; the system further comprising: acontroller adapted to couple with the actuator apparatus and generatethe first control system signal and the second control system signal,and wherein each of the first adjustable vent and the second adjustablevent is controllable by the controller, wherein the controller isconfigured to control an operation of the actuator apparatus so as toalter an amount of flow of the breathable gas exiting each vent, andwherein the operation adjusts the first adjustable vent distinctly fromthe second adjustable vent by coordinating (a) an increase in an amountof a flow of the breathable gas exiting one of the first adjustable ventand the second adjustable vent, with (b) a decrease in an amount of flowof the breathable gas exiting the other one of the first adjustable ventand the second adjustable vent.
 2. The system of claim 1, wherein anadjustment to the first adjustable vent or the second adjustable ventcomprises a change in vent impedance.
 3. The system of claim 1, whereinan adjustment to the first adjustable vent or the second adjustable ventcomprises a change vent cross-sectional area.
 4. A system of claim 1wherein the first adjustable vent and the second adjustable vent arelocated on different sides of the respiratory mask so that they areapproximately symmetrical about a sagittal plane of the respiratorymask.
 5. The system of claim 1, further comprising: a sensor adapted togenerate a first signal, and wherein the controller is configured toprocess the first signal and to generate the first control system signaland the second control system signal.
 6. The system of claim 5, whereinsensor is an orientation sensor and the first signal indicates anorientation of venting apparatus.
 7. The system of claim 5, wherein thefirst signal indicates a pressure of the flow of the supply ofbreathable gas.
 8. The system of claim 5, wherein the first signalindicates a flow rate of the supply of breathable gas.
 9. The system ofclaim 5, wherein the operation is configured to result in an increase insize of an aperture of the one vent simultaneously with a decrease insize of an aperture of the other vent based on a comparison a pluralityof sensor signals.
 10. The system of claim 5, wherein the sensor is amicrophone.
 11. The system of claim 5, wherein the sensor is anaccelerometer.
 12. The system of claim 1, wherein the first adjustablevent and the second adjustable vent each comprise: a plurality of leavesforming a controlled variable size area for communication of a flow ofbreathable gas therethrough from the plenum chamber of the respiratorymask, the plurality of leaves forming a surface around the area; andwherein a cross-section profile of each outer leaf surface is configuredfor exposure to the flow of breathable gas traversing therethrough andto remain constant as the size of the area is varied.
 13. The system ofclaim 12, wherein the operation sets an aperture of the first adjustablevent to a different opening size relative to an aperture of the secondadjustable vent.
 14. The system of claim 1, wherein the operation isconfigured to result in an increase in size of an aperture of the onevent simultaneously with a decrease in size of an aperture of the othervent.